Apparatus for and methods of handling biological sample containers

ABSTRACT

Apparatus for handling biological sample containers comprises a conveyor assembly for conveying containers and a lid handling assembly operable to remove lids from and replace lids onto containers while the containers are in motion on the conveyor assembly. The lid handling assembly comprises a pair of ramps onto which a lid is lifted by a lifting mechanism configured to handle overhanging lids or non-overhanging lids as required. The lid handling assembly may be configured to handle lids of containers of various sizes by altering the ramp spacing. A conveyor assembly comprises a pair of converging rails which carry a pair of jaws operable to carry a container. The convergence of the rails makes the jaws clamp the container so that it is held tightly in position for micro-arraying to be carried out. The conveyor assembly may be adapted to handle different sizes of container by the provision of holders to hold various container types.

BACKGROUND OF THE INVENTION

The invention relates to apparatus for and methods of handlingbiological sample containers, including removal and subsequentreplacement of lids of the containers while the containers are beingconveyed between positions. Especially, but not exclusively, theinvention relates to the handling of Q-trays, omni trays, petri dishesand well plates.

The processing of biological and microbiological samples often includesthe use of arraying and microarraying methods. These methods usemoveable arrays of pins or needles to transfer small amounts of samplefrom one container to another. For example, a cell culture or colony maybe grown in a container of one type, and samples from the colony may betransferred to other containers for subsequent testing.

The pin array is typically moved by computer control over an arrayingsurface on which the containers are arranged in appropriate positions.It is desirable that the containers are held firmly in place during thearraying, to allow accurate collecting and depositing of samples by thepins. Also, processing may be conducted in large volumes, with manysamples requiring to be transferred in a short time. Therefore, it isfurther desirable that pluralities of containers can be placed on andremoved from the arraying surface quickly and accurately.

Several different sizes and shapes of container are typically used, suchas large rectangular Q-trays, smaller rectangular well plates(micro-tite plates) and omni trays, and circular petri dishes. Thecontainers generally have lids to keep their contents safe from spillageand contamination. The style of lid differs between container types.Clearly, the lids need to be removed prior to arraying and replacedagain afterwards. Automation of the lid removal and replacementfacilitates the arraying process, so that a larger volume of containerscan be handled in a given time.

A conventional method of delivering containers to the arraying surfaceuses vacuum suckers to remove and replace the lids. A container with alid is moved, for example on a conveyor belt, to a lid-removal positionat which it is brought to a standstill. A vacuum sucker is lowered downto contact the lid of the container, the vacuum causing the sucker toadhere to the lid. The vacuum sucker is then raised, carrying the lidwith it. The container is then moved on to its arraying position. Afterarraying, the container is moved back to the lid-removal position andbrought to a standstill again. The vacuum sucker is moved downward againso that the lid is lowered on the container. Removal of the vacuumreleases the lid from the sucker. The container, with its lid, is thenmoved on from the lid-removal position.

The removal and replacement of lids in this way tends to slow down theoperation of delivering and removing containers for arraying. Also, itis necessary to accurately locate a container under the vacuum sucker,which requires precise control of the conveyor. This is particularlyimportant for lid replacement, when a lid and container need to beprecisely aligned for lid replacement to be successful. This becomesincreasingly difficult to achieve if a quantity of containers are movedtogether, which it is desirable to be able to do to increase theefficiency of the arraying process.

Hence, there is a requirement for an improved method of, and apparatusfor, handling biological sample containers.

SUMMARY OF THE INVENTION

Accordingly, a first aspect of the present invention is directed toapparatus for handling biological sample containers each having a lid,the apparatus comprising:

a conveyor assembly operable to convey containers between a firstposition and a second position; and

a lid handling assembly operable to remove lids from containers beingconveyed through the lid handling assembly from the first position tothe second position, and to replace the lids onto containers beingconveyed through the lid handling assembly from the second position tothe first position, lid removal and replacement being effected bymechanical interaction between the lids and the lid handling assembly asthe containers are conveyed through the lid handling assembly.

This allows for the automation and speeding up of arraying processeswhich require containers to be arranged on an arraying surface andremoved again afterwards, because there is no requirement for containersto be brought to a halt for lids to be removed or replaced. Also, as thecontainers are not brought to a halt, there is no requirement foraccurate positioning of containers, so that the conveyor assembly doesnot need any precise control as far as the lid handling is concerned.This reduces the complexity and hence cost of the apparatus. However,the apparatus may be brought to a halt during removal or replacement ofthe lids with no detrimental effect. The use of a mechanical interactionbetween the lid and lid handling assembly to remove and replace the lidfurther reduces complexity, as it is possible to contrive lid handlingwith few, if any, moving parts.

Advantageously, the lid handling assembly comprises a pair of rampsarranged such that the conveyor assembly conveys a container between thepair of ramps from the first position to the second position and fromthe second position to the first position, the ramps sloping upward fromlower ramp ends facing towards the first position and arranged such thatthey pass under side walls of the lid of a container being conveyedbetween the pair of ramps from the first position to the secondposition.

The use of ramps provides a particularly simple and attractive way ofremoving and replacing lids, which may be effected with no movingcomponents. Ramps also permit accurate and repeatable lid replacement,with no need for precise location of parts prior to replacement.

The lid handling assembly may further comprise a pair of rotatablerollers, one located in front of each lower ramp end and each rollerhaving an axis of rotation inclined with respect to a perpendicular to aplane in which the containers are conveyed, the rollers operable toengage the lid of a container being conveyed between the pair of rampsfrom the first position to the second position and to direct the lidover the lower ramp ends. The arrangement permits the simplicity ofusing ramps to be further exploited with containers which do not haveoverhanging lids.

In an alternative embodiment, the lid handling assembly comprises a pairof rotatable rollers arranged such that the conveyor assembly conveys acontainer between the pair of rollers from the first position to thesecond position and from the second position to the first position, eachroller having an axis of rotation inclined with respect to aperpendicular to a plane in which the containers are conveyed, therollers operable to grip the lid of a container being conveyed betweenthe rollers from the first position to the second position and feed thelid in a forwardly and upwardly direction.

In one embodiment, the conveyor is further operable to convey containersfrom the first position to a third position after the containers havebeen conveyed from the second position to the first position. Theprovision of three container positions gives greater flexibility to thehandling arrangements. For example, it offers the possibility forcontainers to be unloaded automatically from one storage device, andloaded into a different storage device after arraying, so thatcontainers can be kept entirely separate before and after arraying. Thisis a valuable feature in, for example, testing applications in which itis important that samples do not become muddled.

A second aspect of the present invention is directed to a lid-handlingassembly operable to remove lids from biological sample containers asthe containers are conveyed through the assembly in a first directionand to replace the lids onto the containers as the containers areconveyed through the assembly in a second direction, lid removal andreplacement being effected by mechanical interaction between the lidsand the lid handling assembly as the containers are conveyed through thelid handling assembly, and the assembly being removably mountable on aconveyor assembly operable to convey biological sample containers.

A removably mountable lid handling assembly offers the advantage thatthe assembly can be readily replaced by an alternative assemblyconfigured to handle different sizes or types of lid. Therefore, acontainer handling apparatus can be adapted to handle any of a range ofcontainers, according to user requirements.

A third aspect of the present invention is directed to a storagecassette for storing a plurality of biological sample containers,comprising:

an elongate receptacle for receiving a stack of containers, open atleast an open end; and

at least one movable protrusion located towards the open end andoperable to retain a stack of containers within the receptacle when in afirst position and to let containers pass through the open end when in asecond position.

A storage cassette of this type allows containers to be loaded into andunloaded from it very simply, so that this can be readily performedautomatically by a suitably configured container handling apparatus.This automation increases the efficiency of arraying processes.

A fourth aspect of the present invention is directed to apparatus forconveying biological sample containers, the apparatus comprising:

one or more conveying lanes; and

a conveying device associated with each conveying lane, operable totransport one or more containers along the associated conveying lanebetween a first position in which the conveying device is unengaged withthe one or more containers and a second position in which the conveyingdevice holds the one or more containers.

It is desirable for containers to be held firmly in place duringarraying, so that colonies in the containers can be picked accurately. Aconveying device of this type automatically holds the containers in thecorrect position by gripping them, but also is completely unengaged withthe containers when they are not in this position so that containers canbe easily and quickly placed into and removed from the conveying devicebefore and after arraying.

In a preferred embodiment, each of the one or more conveying lanescomprises a track along which the associated conveying device may move,the track arranged so as to clamp any containers being transportedagainst the conveying device when the conveying device is in the secondposition. The track may comprise a pair of converging rails whichconverge towards the second position.

Use of the track to provide the gripping of the containers means thatthe conveying device can be simple with no moving parts. A trackcomprising converging rails is a particularly straightforward way ofachieving this.

A fifth aspect of the present invention is directed to a holder forholding biological sample containers comprising:

-   -   a plate having shape and dimensions substantially the same as        those of a tray; and    -   one or more recesses in an upper surface of the plate, the or        each recess being shaped to receive a biological sample        container smaller than a Q-tray.

Holders of this configuration can be used with a single containerhandling apparatus to allow the apparatus to handle a range of sizes andshapes of container. Thus the apparatus can be readily modifiedaccording to user requirements.

A sixth aspect of the present invention is directed to an apparatus forworking with biological material, comprising:

-   -   a work surface;    -   a first container handling apparatus, for handling biological        sample containers containing biological material, comprising:        -   a storage assembly operable to store containers, deliver            containers to a first pick-up position, and remove            containers from the first pick-up position;        -   a first conveyor assembly operable to convey containers            between the first pick-up position and a first working            position on the work surface; and        -   a first lid-handling assembly operable to remove lids from            containers as they are conveyed through the first lid            handling assembly from the first pick-up position to the            first arraying position and to replace the lids onto the            containers as they are conveyed through the first lid            handling assembly from the first arraying position to the            first pick-up position, lid removal and replacement being            effected by mechanical interaction between the lids and the            first lid handling assembly as the containers are conveyed            through the first lid handling assembly;    -   a second container handling apparatus, for handling well plates,        comprising:        -   a well plate release mechanism operable to release well            plates from a first storage cassette containing a stack of            well plates and to deliver them to a second pick-up            position;        -   a second conveyor assembly operable to convey well plates            from the second pick-up position to a second working            position on the work surface and from the second working            position to a return position;        -   a second lid-handling assembly operable to remove lids from            well-plates as they are conveyed through the second lid            handling assembly from the second pick-up position to the            second working position and to replace the lids onto the            well-plates as they are conveyed through the second lid            handling assembly from the second working position to the            return position, lid removal and replacement being effected            by mechanical interaction between the lids and the second            lid handling assembly as the containers are conveyed through            the second lid handling assembly; and        -   a well plate loading mechanism operable to transfer well            plates from the return position into a second storage            cassette; and    -   a head carrying a plurality of pins or pipettes operable to move        over the work surface, pick up material from containers in the        first working position and deposit the material in well plates        in the second working position.

This apparatus provides total automation of arraying, gridding and otherprocesses in which biological material needs to be transferred betweencontainers, by handling all containers involved quickly and efficiently,including removing and replacing container lids while the containers aremoving, and providing a plurality of containers in sequence as they arerequired. This permits continuous arraying with a large volume ofcontainers.

A seventh aspect of the present invention is directed to a method ofhandling biological sample containers each having a lid, the methodcomprising:

conveying a container with a lid from a first position through a lidhandling assembly;

arranging a first mechanical interaction between the lid and the lidhandling assembly as the container is conveyed through the lid handlingassembly which removes the lid from the container;

conveying the container without its lid to a second position;

conveying the container without its lid from the second position throughthe lid handling assembly;

arranging a second mechanical interaction between the lid and the lidhandling assembly as the container is conveyed through the lid handlingassembly which replaces the lid onto the container; and

conveying the container with its lid back to the first position.

An eighth aspect of the present invention is directed to a method ofhandling biological sample containers comprising:

placing a container within a conveying device;

moving the conveying device between a first position in which theconveying device is unengaged with the container and a second positionin which the conveying device holds the container.

BRIEF DESCRIPTION OF THE DRAWINGS

For a better understanding of the invention and to show how the same maybe carried into effect reference is now made by way of example to theaccompanying drawings in which:

FIG. 1 shows a perspective view of the exterior of an embodiment of acontainer feeder apparatus according to the invention;

FIG. 2 shows a perspective view of the interior of the container feederapparatus of FIG. 1;

FIG. 3 shows a perspective view of an embodiment of a conveyor assemblyof the container feeder apparatus of FIG. 1;

FIG. 4 shows a further perspective view of the conveyor assembly of FIG.3;

FIGS. 5( a), 5(b) and 5(c) show schematic plan views of part of theconveyor assembly of FIG. 3 in operation;

FIGS. 6( a), 6(b), 6(c) and 6(d) show schematic cross-sectional views ofan embodiment of a lid-handling assembly forming part of the conveyorapparatus of FIG. 3;

FIGS. 7( a), 7(b), 7(c) and 7(d) show perspective and cross-sectionalviews of biological sample containers;

FIGS. 8( a) and 8(b) show perspective views of an embodiment of a holderfor holding biological sample containers according to the invention;

FIG. 9 shows a perspective view of a further embodiment of a conveyorassembly;

FIG. 10 shows a schematic plan view of part of the conveyor assembly ofFIG. 9;

FIGS. 11( a) and 11(b) show perspective views of a further embodiment ofa holder;

FIG. 12 shows a perspective view of a further embodiment of a conveyorassembly;

FIG. 13 shows a schematic plan view of part of the conveyor assembly ofFIG. 12;

FIG. 14 shows a perspective view of an embodiment of a well platestacker apparatus according to the invention;

FIG. 15 shows a perspective view of a cassette for holding well platesfor use with the apparatus of FIG. 12 according to the invention;

FIG. 16 shows an enlarged perspective view of part of the cassette ofFIG. 15;

FIG. 17 shows an enlarged perspective view of part of the well platestacker apparatus of FIG. 14;

FIG. 18 shows an enlarged perspective view of an embodiment of aconveyor assembly of the apparatus of FIG. 14;

FIG. 19 shows a further perspective view of the well plate stackerapparatus of FIG. 14;

FIG. 20 shows a cross-sectional view of a well plate;

FIGS. 21( a), 21(b) and 21(c) show schematic cross-sectional views ofpart of the apparatus of FIG. 14 in operation;

FIGS. 22( a), 22(b), 22(c) and 22(d) show schematic cross-sectionalviews of a lid-handling assembly forming part of the conveyor apparatusof FIG. 3;

FIG. 23 shows a schematic cross-sectional view of the lid-handlingassembly of FIG. 22;

FIG. 24 shows a simplified plan view of an arraying apparatus comprisinga well plate stacker apparatus according to the invention and acontainer feeder apparatus according to the invention.

FIG. 25 shows a perspective view of a further embodiment of a lidhandling assembly;

FIG. 26 shows a perspective view of a still further embodiment of a lidhandling assembly;

FIGS. 27( a) to 27(f) show schematic representations of a furtherembodiment of a well plate release mechanism in various positions;

FIG. 28 shows a perspective view of the well plate release mechanism ofFIG. 27;

FIGS. 29( a) and 29(b) show perspective views of a gripper mechanism ofthe well plate mechanism of FIG. 27;

FIGS. 30( a) to 30(c) shows schematic representations of a pistonmechanism of the well plate release mechanism of FIG. 27;

FIGS. 31( a) and 31(b) show further schematic views of the pistonmechanism of FIG. 30;

FIGS. 32( a) and 32(b) show perspective views of the piston mechanism ofFIG. 30;

FIG. 33 shows a plan view of part of the underside of a well platestacker apparatus comprising the lid handling assembly of FIG. 25 andthe well plate release mechanism of FIG. 27; and

FIG. 34 shows a perspective view of the well plate stacker apparatus ofFIG. 33.

DETAILED DESCRIPTION

First Embodiment

FIG. 1 shows a perspective view of the exterior of a container feederapparatus 10 which is operable to handle containers so as to deliver andretrieve any of a number of biological sample containers having lids andpreviously loaded into the apparatus. The apparatus removes the lid of acontainer on delivery and replaces the lid on retrieval.

The apparatus 10 comprises a storage assembly having a housing 12 withfour walls and a top which define a vertical rectangular column whichsits on a base 28. The housing 12 contains two elevators 34 which arepartly visible through windows 16 in a side wall of the housing 12. Thisside wall of the housing 12 is an opening panel 18 which is hinged tothe housing 12 by hinges (not shown) which allow the panel 18 to openabout a vertical axis, giving access to the elevators 34. A button (notshown) is provided at one side of the panel 18 which controls a latchoperable to keep the panel 18 in a closed position. The panel 18 can beopened by pushing the button to release the latch. A safety interlock(not shown) is provided to control when the panel 18 can be opened,depending on operation of the feeder apparatus 10.

A horizontal elongate aperture 24 is provided in a front panel 20 of thehousing 12, and located approximately half-way up the front panel 20. Aconveyor assembly 26 having a substantially horizontal planarconfiguration protrudes through the aperture 24. An interior portion ofthe conveyor assembly 26 is located within the housing 12 and engageswith the elevators 34, and an exterior portion of the conveyor assembly26 extends outside the housing 12. The conveyor assembly 26 remainsfixed when the panel 18 is opened or closed.

FIG. 2 shows a perspective view of the feeder apparatus with the housing12 removed. The base 28 has mounted upon it a frame 30 which supportsthe elevators 34. The elevators 34 comprise a plurality of verticallyspaced shelves 34. A holder for biological sample containers in whicheach container is arranged on a shelf or other rest is often referred toas a “hotel” arrangement in the art. The illustrated elevators each havetwenty-five shelves, giving a total of fifty shelves. The shelves 32 arevertically movable within the frame 30, the movement being driven by anelevator motor 38. The motors 38 can move the shelves 32 of eachelevator 34 independently or together. The shelves 32 occupy about halfthe height of the housing 12 and frame 30. This gives a sufficientdegree of vertical movement of the shelves 34 to allow each of theshelves 32 to be brought level with the conveyor assembly 26. Movementof the shelves 32 is defined by a plurality of vertical guide bars 42.The guide bars at the side of the elevators 34, some of which arelabelled 42 a in the Figure, are coupled to the panel 18 so that theguide bars 42 a swing away from the elevators 34 when the panel 18 isopened. This gives clear access to the elevator shelves 32.

FIG. 3 shows the conveyor assembly 26 in more detail. The conveyorassembly 36 has a planar configuration comprising a framework 43defining two adjacent conveyors or conveying lanes 44. Each conveyor 44has two long sides each bounded by rails 46, the rails 46 forming atrack, and two ends. The exterior end, on the exterior portion of theconveyor assembly 26, has a buffer 48. The buffer 48 does not extendacross the full width of the conveyor 48, and is located centrally withrespect to the width of the conveyor 48. The rails 46 of each conveyor44 are angled with respect to each other in the horizontal plane, andconverge towards the exterior end. The exterior portion of the conveyorassembly 26 has a delivery surface 50 which extends across the width ofeach conveyor 44 just below the height of the rails 46. The interiorportion of the conveyor assembly 26 has no such surface, so that anopening 52 is present in each conveyor 44 extending between its rails46.

The conveyor assembly 26 is located within the housing 12 so that eachconveyor 44 is in line with an elevator 34. The conveyor assembly 26 isfastened to the frame 30 and supported underneath by a horizontal bar 40extending across the frame 30. Each elevator shelf 32 is free to movevertically through the opening 52 in its respective conveyor 44. Theelevator motors 38 can move the elevator shelves 32 and position them sothat an elevator shelf 32 from each elevator 34 is at the same height asthe delivery surface 50.

Each conveyor 34 is equipped with a conveying device 54. Each conveyingdevice comprises a pair of sliding jaws 56. The jaws 56 are mounted onthe rails 46, one on each side of the conveyor 44. Each jaw 56 can beslid along its rail 46 by a motor-driven belt drive 58 which is operableto move the jaw 56 to and from a first position at the interior end ofthe conveyor assembly 26 and a second position at the exterior end ofthe conveyor assembly 26. Each jaw 56 is driven separately, and the jaws56 are not connected together in their pairs, but the belt drives 58operate so as to move each pair of jaws 56 together to maintain theintegrity of the conveying devices 54. Owing to the convergingarrangement of the rails 46, the jaws are closer together in the secondposition than the first position.

Each jaw 56 is elongate along its direction of travel, and has a shapedflange 59 projecting from its inner surface towards the centre line ofthe conveyor 44. The end of the flange 59 closest to the interior end ofthe assembly 26 is shaped to form a large dog 60, which protrudes beyondthe flange 59. Similarly, the end of the flange 59 closest to theexterior end of the assembly 26 is provided with a small dog 62 whichalso protrudes towards the centre line of the conveyor 44. The flange 59and both dogs 60, 62 have a vertical thickness which is less than thevertical thickness of the jaw 56. The corners defined by the dogs 60, 62meeting the flange 59 and which face each other are rounded, so that thesides of the dogs 60, 62 and the side of the flange 59 define a shallow‘U’ shape. The ‘U’ shape is lined with rubber.

The extent of travel of the jaws 56 is such that the small dogs 62 cantravel past the first edge of the buffer 48.

Each conveyor also comprises a lid-handling assembly 63, operable toremove and replace the lids of containers travelling on the conveyors.Each side of each conveyor 44 is provided with a low vertical wall 64positioned about half-way along the conveyor 44. The inner surface ofeach wall 64 (i.e. the surface facing towards the opposite wall) has anintegral ramp 66 extending from it over the conveyor, and slopinggenerally upwards from lower ramps ends at the end of the wall 64nearest the interior end of the assembly 26. Each wall 64 is spacedapart from the rail 46 along the side of the conveyor 44 so that the jaw54 can pass along the rail 46 without hitting the wall 64. The loweredge of each wall 64 and ramp 66 is positioned at a height which allowsthe flange 59 and dogs 60, 62 of the jaw 56 to pass under the wall 64and ramp 66.

Each ramp has two portions, each with a different gradient. The initial,lower ramp portion 68 has a slope of approximately 30° with thehorizontal, and the upper ramp portion 70 has a much shallower slope, ofapproximately 5° to the horizontal.

The walls 64 and their ramps 66 are connected together by a pair ofhorizontal rods 72 which pass through holes 74 in the walls 64 andextend across the width of the conveyor assembly 26 above the conveyors44. The ends of the rods 72 are held in brackets 74, with one bracket 74on each side of the assembly 26. The brackets 74 are removably fastenedto the outer sides of the framework 43 of the assembly 26, for examplewith nuts and bolts. By unfastening the nuts and bolts, the ramps 66,walls 64, rods 72 and brackets 74 can be removed from the conveyorassembly 26 as a single piece comprising the lid-handling assembly 63.

FIG. 4 shows a perspective view of the underside of the conveyorassembly 26. The belt drives 58 used to move each jaw 56 are visible.They comprise, in the conventional manner, a belt 55 passing around aseries of rollers 57. The belts of the two central drives have not beenincluded, to show the rollers 57 a more clearly.

Preferably, a controller such as computer is provided to controloperation of the feeder apparatus 10, by operating the elevator 14 viathe elevator motors 38 and the conveying devices 54 via the belt drives58. The computer may be preprogrammed with a sequence of commands.

Some of the dimensions of the feeder apparatus 10 are determined inaccordance with the type of container to be handled. The embodimentillustrated in FIGS. 1, 2, 3 and 4 is configured to handle containersknown as Q-trays. These are large flat generally square plastic traysmeasuring 235 mm by 235 mm by 16 mm or more deep, which have roundedcorners and a low wall. The trays have lids which also have roundedcorners and which fit loosely over the trays so that the edge walls ofthe lid overhang the tray. The walls of the lid are shorter than thewalls of the tray so that there is a gap between the lower edge of thelid wall and any surface on which the tray rests.

In accordance with this, the elevator shelves 32 are each large enoughto accommodate one Q-tray. The shelf area is approximately the same asthe area of a Q-tray. The spacing between vertically adjacent shelves 32must be sufficient to accommodate the height of a Q-tray with a lid. Theopenings 52 must be large enough to let the elevator shelves 32, withthe Q-trays on, pass vertically through them when the jaws 56 arepositioned at the extreme interior end of the conveyor assembly 26. Acertain amount of clearance is preferably provided, so that rails 46 arespaced so that the distance between the jaws 56 (base of ‘U’ shape tobase of ‘U’ shape) at this position is the width of a Q-tray plus about25 mm. Similarly, the length of the jaws 56 is defined so that thedistance across each ‘U’ shape is the length of a Q-tray plus about 25mm.

When the jaws 56 are in the second position, at the exterior end ofconveyor apparatus 26, they are designed to hold a Q-tray firmly, aswill be described in more detail later. Therefore, the rail spacing atthis end is arranged to that the distance between the jaws 56 is thewidth of a Q-tray. At all points along the rails 56, the distance fromone large dog 60 to the opposite large dog 60, and the distance from onesmall dog 62 to the opposite small dog 62 is less than the width of aQ-tray. In this way, a Q-tray is encompassed by the jaws on all sides atany position along the rails 56.

Regarding the ramps 66, these protrude over the conveyors 44 to anextent such that the spacing between them is just sufficient to let aQ-tray pass between them, but the spacing is less than the width of theoverhanging lid of the Q-tray.

These dimensions will need to be altered accordingly if the apparatus isto handle containers of other sizes.

The operation of the feeder apparatus 10 will now be described.

Initially, the conveying devices 54 are positioned in the firstposition, at the interior end of the conveyor assembly 26.

The panel 18 of the housing 12 is opened by using the button. Q-trayswith lids on are placed in the elevators 34, one per elevator shelf 32,using as many shelves 32 as are required. The Q-trays contain culturedcolonies of biological samples. The panel 18 is then closed, and theapparatus 10 is activated by the controller.

The elevator motors 38 move the elevators 34 vertically until anelevator shelf 32 containing a Q-tray 76 in each elevator 34 is levelwith the delivery surface 50 of the conveyor assembly 26. The Q-trays 76on the shelves 32 are therefore encompassed by the jaws 56 of theconveying devices 54.

FIG. 5( a) shows a schematic plan view of a Q-tray 76 in this position.The Q-tray 56 is located within the jaws 56, which have rubber linings77, but spaced apart from the jaws 56 by the clearance gap 78 requiredto permit easy vertical travel of the elevator 14.

Once the Q-trays 76 are in this position, the elevators 34 stop, and thecontroller activates the belt drives 52 to move the jaws 56. Consideringjust one conveyor 44, the jaws 56 move forwards along their rails 46until the large dogs 60 abut the rear wall of the Q-tray 76, at whichpoint the jaws 56 start to push the Q-tray 76 forwards. The Q-tray 76 ispushed off the elevator shelf 32 and onto the delivery surface 50. Thejaws 56 carry the Q-tray 76 through the lid-handling assembly 63, theoperation of which is described in detail below, and the Q-tray 76emerges from the lid-handling assembly without its lid 75. The jaws 56continue to push the now lidless Q-tray 76 forwards until the front wallof the tray abuts the buffer 48. In this position (the second position),the Q-tray 76 is tightly held between the jaws 56. This is because theconvergence of the rails 46 brings the jaws 56 closer together as theymove forwards so that the clearance gap 78 is closed and the rubberlining 77 comes into contact with walls of the Q-tray 76. The rubberlining 77 gives a high friction contact between the jaws 56 and theQ-tray 76.

FIG. 5( b) is a schematic plan view of the Q-tray 76 and jaws 56 in thisposition, showing how the Q-tray 76 is held between the jaws 56 and heldin place by the rubber lining 77. The large dogs 60 are in contact withthe rear wall of the tray 76, having pushed the tray 76 into position.Also, in FIG. 3, the Q-tray 76 b on conveyor 44 b is shown in the heldposition.

When the Q-tray 76 reaches the second position, it is ready for colonypicking as part of an arraying process to be performed. This istypically achieved by using a camera to photograph the contents of thetray. The photograph is processed by computer to obtain co-ordinates ofcolonies in the tray. The computer then uses the co-ordinates to enableit to control an array of pins or needles which are moved and dippedinto the colonies to obtain samples which can then be transferredelsewhere, such as to another tray. Therefore it is important to be ableto accurately maintain the position of the Q-tray, so that the coloniesremain at their measured co-ordinates. However, it is possible that thepins may impact on the bottom of the tray, which could cause the tray toslip out of position. Hence the feeder apparatus 10 features jaws 60that are provided with a rubber lining 77, so that trays are tightlyheld and inhibited from being knocked out of position.

After colony picking, the drive belts 58 are driven in reverse so thatthe jaws 56 travel along the rails 46 towards the elevator 14, takingthe Q-tray 76 with them. The diverging rails 46 cause the jaws 56 toopen, so that the Q-tray 76 is held less tightly, and eventuallyreleased. When this happens, the jaws 56 move past the Q-tray 76 untilthe small dogs 62 come into contact with the front wall of the Q-tray76.

FIG. 5( c) shows a schematic plan view of the Q-tray 76 and jaws 56 justbefore the tray 76 is picked up by the small dogs 62. When this hashappened, the moving jaws 56 pull the Q-tray along, through thelid-handling assembly 63 which replaces the lid 75, and back to thefirst position, on the elevator shelf 32. The elevators 34 then movevertically to present further Q-trays to the first position to bedelivered by the conveyor assembly 26 for colony picking.

FIGS. 6( a) to 6(d) show a series of simplified cross-sectional sideviews of a Q-tray 76 and a ramp 70 to illustrate the operation of thelid-handling apparatus 63.

In FIG. 6( a), the Q-tray 76 has its lid 75 on, and is being carriedtowards the ramps 66 by the jaws which each have a large dog 60 and asmall dog 62. The large dog 60 pushes against the rear wall of theQ-tray 76.

The lower edges of the ramps 66 are below the height of the lower edgeof the lid 75. As the Q-tray 76 reaches the start of the ramps 66, theoverhanging lid 75 hits the front of the ramps 66, which are able topass under the edges of the lid 75. The Q-tray 76 can move past theramps 66, as it is narrower than the spacing between them, and the dogs60, 62 are small enough to pass under the ramps 66. Therefore, as theQ-tray 76 is pushed forwards, the lid 75 begins to climb the ramps 66,as shown in FIG. 6( b). Hence the lower, front ends of the ramps act asa lifting mechanism to lift a lid onto the ramps. The large dogs 60 arein contact with the rear of the Q-tray 76 and the lid 75, so that thelid 75 is pushed up the ramps 66 as the Q-tray 76 continues to be pushedforwards. Eventually, the lid 75 is lifted by the ramps to a heightsufficient to let the large dogs 60 pass under the lower edge of the lid75, and push the Q-tray 76 forwards without the lid 75, as shown in FIG.6( c). The lid 75 remains on the ramps 66 as the Q-tray is pushedtowards its final position for colony picking. FIG. 6( d) shows thisarrangement. The walls 64 extending above the ramps 66 have a spacebetween them just sufficient to accommodate the width of the lid 75 sothat the lid 75 is maintained in the correct lateral position.

The ramps 66 have two sloped sections, the initial, lower ramp portionor section 68 being much steeper than the secondary, upper ramp portionor section 70. The steep initial sections 68 lift the front of the lid75 quickly to remove it from the path of the advancing Q-tray 76. Theshallow secondary sections 70 lift the lid at a slower rate, but permitit to rest at a shallow incline so that it does not slip down the rampsunder gravity once the large dogs 60 have passed under it.

After colony picking, the lid 75 is replaced on the Q-tray 76 by aprocess that is substantially the reverse of the lid removal process.The small dogs 62 pull the Q-tray 76 back towards the ramps 66. Therelative heights of the dogs 60, 62 and the Q-tray wall mean that thelid removal process leaves the lid 75 at a height at which its loweredge is below the upper edge of the Q-tray wall, but above the largedogs 60. Hence, the large dogs 60 pass under the lid 75 on the ramps 66,but the rear wall of the Q-tray 76 hits the rear wall of the lid 75 andbegins to pull the lid 75 down the ramps 66 as the Q-tray 76 proceeds.Eventually the lid 75 is pulled right off the ramps 66 and falls ontothe Q-tray 76 in the correct orientation so that the Q-tray 76 isproperly covered by the lid 75.

Hence, the lid removal and lid replacement for the Q-trays is performedwhilst the Q-trays are in motion; indeed, the motion contributes to theprocess. No moving components additional to those already provided tomove the Q-trays are required to remove and replace the lids. TheQ-trays can be delivered for picking much more quickly than is possiblywith conventional lid removal methods using vacuum suction, as there isno need to bring the Q-trays to a halt for lid removal. Also, the lidsare conveniently replaced on the move as well, in such a way as to avoidany requirement for precise alignment between lid and tray.

The feeder apparatus 10 may be readily adapted for the lid removal,delivery and lid replacement of other types of biological samplecontainer. This flexibility arises from the fact that the feederapparatus 10 is configured to handle Q-trays, which in general have thelargest area, or footprint, of all relevant types of container.

FIG. 7( a) shows a perspective view of a Q-tray 76 with its lid 75 on,illustrating that it is a large flat rectangular tray with roundedcorners and an overhanging lid as described above. FIG. 7( b) is aperspective view of a container type known as an omni-tray. This is alsoa flat rectangular tray 80 with a lid 82, but it has a footprint lessthan half that of a Q-tray 76, as it measures 128 mm by 86 mm. It hastwo adjacent square corners, with the remaining corners being truncated.FIG. 7( c) is a perspective view of a petri dish 88, which is a roundcontainer with a lid 90 and a diameter of 88 mm. Therefore, it has afootprint of a size such that four petri dishes can fit within the areaof a Q-tray.

Both the omni-tray and the petri dish have overhanging lids of the sametype as the Q-tray. FIG. 7( d) shows a simple cross-section of acontainer 88 having such a lid 90. The lid 90 fits over the container 88so that its side walls 92 overhang the container 88 but do not reach allthe way down the side 94 of the container 88. This lid design means thata ramp arrangement similar to that used in the feeder apparatus 10 toremove lids from Q-trays can also be used to remove lids from omni-traysand petri dishes. The ramp arrangements operate on the same principle asthat used with Q-trays, but are more closely spaced to handle smallercontainers.

The Q-tray feeder apparatus 10 can handle other containers if a holderto hold the containers is provided. The holder is a flat plate the samesize and shape as a Q-tray, and having shallow depressions or recessesin its upper surface of a shape corresponding to the shape of thecontainers.

FIG. 8( a) shows a perspective view of a holder 96 for handlingomni-trays. The holder 96 is made from plastics material and has twoshallow rectangular recesses 98 for receiving two omni trays. Along oneedge of each recess 98 there are two supplementary dogs 100 having theform of abutments which abut the rear surface of omni-trays and theirlids when placed in the depressions. The supplementary dogs 100 arespring-loaded so that they are urged forwards against the omni-tray lidwhen that is in place, and then move forwards further to abut the wallof the omni-tray after the lid is removed. The supplementary dogs 100therefore hold the omni-tray firmly in position so that it does not moveduring colony picking. The holder 96 has a finger slot 102 in each sideto facilitate picking up of the holder 96.

FIG. 8( b) shows a perspective view of the holder 96 containing twoomni-trays 80 without lids. The omni-trays are located one behind theother with respect the direction in which they are carried through thelid-handling apparatus. Therefore, the lid-handling apparatus needs tobe able to accommodate two lids, and remove and replace the lids one ata time as the respective omni trays pass between the conveyors.

FIG. 9 is a perspective view of a conveyor apparatus 26 adapted tohandle omni-trays. As the omni-trays are held in holders which are thesame size and shape as Q-trays, the elevators 34 and conveyors 44 canhandle the omni-trays with no modifications. The only adaptationnecessary is to the lid-handling assembly 63, to provide ramps and wallswhich are suitably spaced. Therefore, the conveyor assembly shown inFIG. 9 is the same as that shown in FIG. 3 and previously described,with the exception of the lid-handling assembly 63. The conveyorassembly 26 is shown with one conveyor 44 a with a holder 96 acontaining two omni-trays 80 with lids 82 which has just been returnedto the elevator shelf 32 by the jaws 56 (the holder 96 a is abutting thesmall dogs 62 which have just pulled it along). The other conveyor 44 bshown has a holder with two omni-trays delivered to the colony pickingposition which have had their lids 82 removed by the lid-handlingassembly 63. The conveyor assembly 26 and lid-handling assembly 63operate in substantially the same manner as described for the Q-trayhandling.

As mentioned previously, the Q-tray lid-handling assembly 63 isremovably mounted on the conveyor assembly 26. Therefore, it isstraightforward to replace it with a lid-handling assembly 63 configuredto handle omni-trays. As before, the lid-handling assembly 63 comprisesa pair of walls 64 with integral ramps 66 per conveyor 44, but they aremounted so that each of ramps 66 is spaced apart with sufficientclearance for an omni-tray to pass between them but to pick up the lidof the omni-tray. The spacing between the walls is just sufficient toaccommodate the lid. Also, the height of the ramps 66 and walls 64 issuch as to let the holder 96 pass underneath, but allow the ends of theramps 66 to engage with the edges of a lid to lift it. The length of theramps is sufficient for two omni tray lids to sit on the ramps, onebehind the other. As before, the walls 64 and ramps 66 are mounted onhorizontal bars 72 held in end brackets 74 which are mounted onto theconveyor assembly 26.

Again as before, the ramps 66 have two sections or portions of differinggradient. However, the omni-tray ramps 66 have an initial lower rampportion 104 followed by a longer steeper upper ramp portion 106. Thepurpose of this is to give better handling of the two lids 82 which arehandled by a single pair of ramps 66. During lid removal, the lid 82 aof the front omni-tray is lifted and removed by the ramps 66 and sits atthe bottom of the slope. As the rear omni-tray arrives, the ramps liftits lid 82 b, which pushes the front lid 82 a further up the ramps 66until both lids 82 are on the ramps 66. When the lids are replaced, thesteep section 104 allows the front lid 82 a to slide down the ramps 66under gravity as the rear lid 82 b is removed by the returning rearomni-tray. The front lid 82 a reaches the bottom of the ramp as the rearlid 82 b falls onto the rear omni-tray, and is in the correct positionto be picked up by the returning front omni-tray.

The lid-handling assembly 63 also comprises a retainer in the form of aspring-loaded arm 108 on each wall 64. The arm 108 is pivotally mountedat a first end on the outer side of the wall 64 in a mount 110. A secondend of the arm 108 turns at an angle to the length of the arm to form ahook 112, the end of which passes through a hole 114 in the wall 64 toprotrude over the ramp 66. The spring-loading lightly biases the hook112 to protrude through the hole 114.

The arms 108 are provided to keep the lids 82 in place on the ramps 66.The front lid 82 a is liable to slide under gravity down the steepsection 106 and push the rear lid 82 b off the ramps, which willinterfere with the ability of the rear omni-tray to pick up the rear lid82 b. The arms 108 stop the lids 82 from sliding.

As the front lid 82 a is lifted by the ramps 66, it abuts the hooks 112and pushes the arms 108 outwards and away from the ramps 66, and movesup the ramps 66. The rear lid 82 b then arrives and pushes the front lid82 a further up the ramps 66. When both lids 82 have moved up the rampsfar enough for the rear lid 82 b to have passed the hooks 112, the arms108 spring inwards so that the hook 112 protrude over the ramps 66again. The hooks 112 stop the lids 82 from sliding under gravity. Whenthe lids 82 are picked up by the returning omni-trays, the pullingaction of the trays on the lids 82 is sufficient to force the armsoutwards again so that the lids 82 are released. Therefore, the hooks112 on the spring-loaded arms 108 are abutments which abut the lids andkeep them on the ramp, but are also movable so as to move out of the waywhen the lids are required to move off the ramps.

FIG. 10 is a plan view of the lids 82 held on the ramps 66 by thespring-loaded arms 112. This shows how the hooks 112 pass through theholes 114 to protrude over the ramps 66.

This arrangement allows the lids of two omni-trays held on a singleholder to be removed with a single pair of ramps. The holder 96 is of asufficient size to accommodate two omni-trays, so that four omni trayscan be delivered at one time, and the elevators having twenty-fiveshelves each can together handle one hundred omni-trays. However, ifdesired, holders adapted to hold one omni-tray per holder could beprovided.

FIG. 11( a) shows a perspective view of a holder 116 for handling petridishes. The holder 116 is made of plastic and has four shallow circulardepressions or recesses 118 for receiving four petri dishes arranged ina rectangular formation. Hence two rows of two petri dishes can beaccommodated. The holder 116 has a finger slot 102 in each side tofacilitate picking up of the holder 116. The back edge of each recess118 has a supplementary dog 120 in the form of an abutment which abutsthe rear surface of a petri dish and its lid when the dish is placed inthe recess, and acts to urge the lid up the ramps during lid removal.Each recess also has two grips comprising barbed spikes 122 positionedat its edge approximately 180° apart and protruding slightly over therecess 118. The spikes 122 hold the petri dishes firmly in positionduring colony picking so that they do not move within the recesses 118.The spacing of the spikes by 180° facilitates loading of the petridishes into the holders 116, as the dishes can be slipped in from theside.

FIG. 11( b) shows a petri dish holder 116 with a petri dish 84, withouta lid, held in each depression 118.

FIG. 12 shows a perspective view of the conveyor assembly 26 adapted tohandle petri dishes. The holders 116 are handled in the same way asQ-trays, so that the only modification required to the assembly is theprovision of a lid-handling assembly appropriate for petri-dishes.

As there are two rows of petri dishes 84 across the width of the holder116, the lid-handling assembly 63 comprises two pairs of ramps 66 acrossthe width of each conveyor 44, with each ramp of a sufficient size toaccommodate two petri dish lids 86. As before, each ramp 66 is integralwith a wall 64. Each pair of ramps 66 is positioned and spaced to engagewith the lids 86 from one row of petri dishes 84, with the correspondingwalls 64 spaced to accommodate the lids 86. The walls 64 and ramps 66are at a height to allow the holders 116 to pass underneath them, andare spaced apart from the rails 46 to allow the jaws 56 to slide freely.The walls 64 and ramps 66 are held on horizontal bars 72 with endbrackets 74 mounted on the conveyor assembly 26 as before.

The walls are provided with retainers in the form of spring-loaded arms108 having hooks 112 protruding through holes 114 in the walls. Thesearms 108 operate in the same way as the arms described for the omni-traylid-handling assembly, and act to keep the lids 86 up on the ramps 66.As before, the ramps 66 have an initial lower ramp portion or section104 with a shallow gradient and a secondary upper ramp portion orsection 106 with a steeper gradient. The steep slope allows the lid 86 awhich is held highest up the ramp 66 to slide down under gravity oncethe lower lid 86 b is removed, but the arm is needed to prevent bothlids from sliding down the ramps 66 while the lids 86 are held duringthe colony picking.

In addition to the lid handling features already described for theQ-tray and omni-tray lid handling, the petri dish lid handling assemblyhas a fixed guide arm 124 positioned above each pair of ramps 66. Eachguide arm 124 is held on one or both of the horizontal bars 72 midwaybetween the corresponding pair of ramps 66. The underside of each guidearm 124 is shaped to approximately follow the slope of the ramps 66, butthe guide arm 124 is positioned so the its underside is in a plane whichis spaced apart from the plane of the ramp slope by a distance slightlygreater than the height of a petri dish lid. Therefore, when the lids 86are on the ramps 66, a guide arm 124 is positioned slightly above thetop surface of the lids. The guide arms 124 act to keep the lids 86sitting flat on the ramps 66. As the lids 86 are round, there is only asmall part of the edge of a lid 86 in contact with each ramp, theseparts being on opposite sides of the diameter of the lid 86. Hence, thelids 86 can pivot or rock on the ramps 66, and possibly ride up over oneanother, which would interfere with lid removal and replacement. Theguide arms 124 are provided to prevent this, by confining the lids sothat they are not able to pivot enough to cause any problems of thistype.

FIG. 13 is a simplified plan view of four petri dish lids 86 which havebeen removed from their dishes, the dishes being held in a singleholder, and which are held on ramps 66 of the lid handling assembly. Thespring-loaded arms 108 stop the lids 86 from sliding down the ramps 66.There is only one spring-loaded arm 108 per pair of ramps 66; this isbecause there is insufficient space between the two central walls 64 a,64 b to accommodate arms of this type. However, a similarly-operatingbut more compact spring-loaded catch device could be used if it wasfound that the lids needed to be held on both sides.

This embodiment of the feeder apparatus is thus capable of delivering upto eight petri dishes for colony picking at one time, and removing andreplacing their lids quickly on the move. The two elevators withtwenty-five shelves each can hold up to two hundred petri dishes in therelevant holders.

The ease with which the container feeder apparatus can be adapted tohandle different container types means that the apparatus can besupplied with just one lid handling assembly so that the apparatus issuitable for use with a particular container type, or with a pluralityof lid handling assemblies so that a user may configure the apparatus tohis particular requirements as any time.

The feeder apparatus 10 can be modified to handle a greater or lessernumber of containers. For example, a greater number of elevator shelvescan be provided per elevator. Also, the apparatus could be provided withmore than two conveyors and two elevators, which would increase thenumber of containers which could be delivered at one time. On the otherhand, a more compact apparatus with one conveyor and one elevator wouldbe suitable for lower volume container handling. To provide furtherflexibility, the control of the apparatus can be configured to allow theconveying devices to be driven independently, so that any selectedconveyor or conveyors can be used at a given time.

A further alternative is that the apparatus could be configured toaccommodate larger holders, rather than holders of the same shape andsize a Q-tray. For example, holders large enough to hold six petridishes, or three omni trays could be provided. Holders having recessesto hold Q-trays would be required to allow an apparatus configured inthis way to handle Q-trays. The use of larger holders permits a largervolume of containers to be handled. It is necessary to provide rampshaving sufficient length to accommodate the number of lids which are tobe conveyed through the lid handling assembly at one time.

Holders having recesses of other shapes and sizes can be provided toallow the apparatus to handle other types of container. Lid handlingassemblies similar to that described are suitable for any containerhaving an overhanging lid of the type illustrated in FIG. 7( d).

However, there are biological sample containers which do not haveoverhanging lids, but which are commonly used for arraying. Well platesor micro-tite plates are examples of such containers. The lid handlingassemblies described so far are not suitable for these containers, asthere is no overhang on the lid for the front, lower end of the ramps toengage under to lift the lid. Therefore, a different arrangement isrequired to provide for lifting a non-overhanging lid onto the ramps.However, once on the ramps, lid removal can proceed as described foroverhanging lids, and lid replacement can be achieved in the same way asfor overhanging lids.

Second Embodiment

FIG. 14 shows a perspective view of a well plate stacker apparatus whichis operable handle containers in the form of well plates so as tosequentially deliver a quantity of stacked well plates and retrieve andrestack the plates in sequence. The apparatus removes the lids of thewell plates on delivery and replaces the lids on retrieval.

The well plate stacker apparatus 200 comprises a flat bed 202 which isprovided on its lower surface with a bracket 204 by which the apparatusmay be bolted to further apparatus (not shown). One end of the flat bed202 is provided with a delivery, or conveyor, bed 206. The delivery bed206 has three parallel delivery, or conveyor, lanes 208 which extendlongitudinally along the delivery bed. Each of the delivery lanes 208 isprovided with a lid handling assembly 218. Each lid handling assembly islocated adjacent to the respective feed port 209 of each delivery lane208, with the delivery lanes 208 extending beyond the lid handlingassembly 218.

Towards the centre of the flat bed 202 at one end of the delivery lanes208 there are arranged three feed ports 209, one for each of thedelivery lanes 208. Each feed port 209 comprises a framework adapted toreceive the lower end of an upright cassette 216. Each feed port 209 isprovided with a release mechanism in the form of two escapementmechanisms 210. Behind each feed port 209 there is located a stackingport 212, each stacking port 212 being in line with one of the deliverylanes 208. Each stacking port 212 also comprises a framework adapted toreceive the lower end of a cassette 216. Each stacking port 212 isprovided with a plurality of lifting members 214, which are verticalrods of square cross-section.

Each of the cassettes 216 is identical. However, the feed ports 209 andstacking ports 212 are configured such that cassettes inserted into thefeed ports sit at a lower height than cassettes in the stacking ports212. In FIG. 14, two of the feed ports 209 are shown with a cassette 216inserted therein, as are two of the stacking ports 212.

FIG. 15 shows a cassette 216 in more detail. The cassette 216 iselongate and has the general shape of a rectangular prism. The cassette216 comprises an external framework which has four elongate uprightmembers 220 which define the edges of the cassette. The upper ends 223of the upright members 220 are joined together by cross-pieces 222. Thelower ends 221 of the upright members 220 define a supporting portion onwhich the cassette 16 can sit. The lower ends 221 are provided with legportions 224. There are two leg portions 224, each having a cross-bar226 connecting two adjacent upright members 220. Each cross-bar 226 hasa leg 228 extending downwardly from each of its ends, such that there isone leg 228 provided for each of the upright members 220. The uprightmembers 220, the cross-pieces 222, and the leg portions 224 define areceptacle which is adapted to receive a quantity of well plates stackedon upon the other. The cassette 216 shown is configured to hold fiftywell plates, but cassettes of a size to hold a greater or lesser numberof well plates may be provided if desired. The well plates may beinserted into the cassette through its upper end defined by thecross-pieces 222, or from underneath, or through the sides. To retainthe stack of well plates within the cassette, each of the legs 228 hason its inside surface a spring-loaded latch 230.

FIG. 16 shows a perspective view of the lower end of the cassette 116,including the leg portions 224 and the latches 230, in more detail. Thelatches 230 each have a small movable protrusion 232 which protrudesinto the inner volume of the cassette 216. The latches 230 arespring-loaded such that the protrusions 232 are biased in thisprotruding position. Each protrusion 232 has a support surface 231 and asecond surface 229. The support surface 231 faces upwards and is incontact with the lower surface of the bottom-most well plate of a stackheld within the cassette 116. Therefore, the support surfaces 231support the stack of well plates within the cassette 216. The secondsurface 229 forms an obtuse angle to the support surface 231 and facesgenerally inwards and downwards. The spring-loading of the latch 230 isconfigured such that pressure on the second surface 229 causing theprotrusion 232 to move backwards and into its respective leg 228 so thatit no longer protrudes into the cassette volume. Hence the latches 230may be released, allowing well plates within the cassette 216 to fallout from the bottom of the cassette 216. The cassette 116 of FIG. 16 hasfour latches, but a greater or smaller number may be provided asappropriate, depending on the weight of the stack of well plates whichare to be supported within the cassette.

FIG. 17 shows a feed port 209 in more detail. The flat bed 202 forms thebottom surface of the feed port 209. The feed port 209 is substantiallyrectangular and there are four apertures 235 in the flat bed 202 locatedone towards each of its corners. The apertures 235 are placed such thata cassette 216 placed into the feed port 209 will sit with its lower end221 located against the flat bed 202 and its legs 228 protruding throughthe apertures 235.

The two sides of the feed port 209 which are parallel to the directionof the delivery lane 208 are provided each with an escapement mechanism210. Each escapement mechanism 210 comprises an elongate hinged member233 which is moveably fastened within the feed port 209 such that it ishinged about an axis parallel to the delivery lane 208. The lower end ofthe hinged member 233 has a supporting flange 234 which protrudes alittle way into the feed port 209. The separation of the flanges 234 oneach escapement mechanism 210 is less than the width of a well plate.Each hinged member 233 is further provided with a elongate grippingportion 236 which runs along the length of the hinged member and islocated above the supporting flange 234 and spaced therefrom by a heightsubstantially equal to the height of one and a half well plates. Thegripping portion 236 has a rubber surface. The separation between thegripping portion on one escapement mechanism 210 and gripping portion236 on the opposite escapement mechanism 210 is slightly more than thewidth of a well plate.

When a cassette 216 containing well plates is inserted into the feedport 209 the legs 228 of the cassette pass through the apertures 235 sothat the latches 230 are underneath the flat beds 202. The supportingflanges 234 catch on the bottom-most well plate of the stack of wellplates held within the cassette 216, and support the stack within thecassette 216. Hence when a cassette 216 is in this position, the wellplates held therein are not supported on the latches 230, but instead onthe flanges 234 of escapement mechanisms 210.

FIG. 18 shows a perspective view of the delivery bed 206 in more detail.Each of the three delivery lanes 208 of the delivery bed 206 aresubstantially identical. Each delivery lane 208 has a longitudinal slot240 running along its centre and terminating before the ends of thedelivery lane 208. Each delivery lane 208 has a stop-bar 245 runningacross its end. Each delivery lane 208 also has a movable pushing dog242 and a pick-up catch 244. The pushing dog 242 and the pick-up catch244 are operable to move along the length of the slot 240, and aredriven by means of a sliding plate located on the underside of thedelivery beds 206. The pushing dog 242 and the pick-up catch 244 areconnected through the slot 240 to the sliding plate. The sliding plateis driven by a motor (not shown) via a worm drive. A belt drive couldalso be used. The pick-up catch 244 has two positions, one being apicking up position, which is shown in FIG. 18, in which it protrudesabove the slot 240, and the other position being an inoperable positionin which it lies below the plane of the delivery bed 206 and does notprotrude through the slot 240. The pushing dog 242 and pick-up catch 244can be moved from a home position indicated by reference numeral 213 onFIG. 14 to the end of the slots 240, at which point the pushing dog 242is spaced from the stop bar 245 by approximately the length of a wellplate. The pushing dog 242 is spring-biased against the sliding platesuch that it is urged in a direction towards the stop-bar 245.

Each delivery lane 208 also has a pair of walls 246 located one on eachside of the delivery lane 208, and facing one another. The inner surfaceof each wall 246 has a ramp 248 which extends upwards from a lower rampend closest to the feed ports 209 towards the stop-bar 245.

A roller 250 is located at the lower end of each ramp 248. Each roller250 is mounted on an axle such that the roller is freely rotatablethereon, and is mounted at an angle such that its axis of rotation issubstantially perpendicular to the slope of the ramp and parallel to thesides of the walls 246. The angle may typically between 1° and 10° orbetween 1° and 5°, for example, 4°. Each roller 250 comprises aplurality of ball races stacked one upon the other, and surrounded by atubular sleeve of a rubber material having a high coefficient offriction, such as santoprene. The axles of the rollers 250 extendthrough the delivery bed 206 and are mounted on spring-loaded mountssuch that the rollers 250 are biased towards the slot in theirrespective delivery lane 208, but can move under light pressure on theaxle in a direction substantially perpendicular to the slot 240 and awayfrom the slot 240. When in the biased position each roller 250 is spacedfrom the roller 250 on the opposite ramp 248 by a distance which is afew millimetres less than the width of a well plate. The spring-loadednature of the mounts allows the rollers 250 to be pushed apart to aseparation of more than the width of a well plate lid. The rollersprovide a lifting mechanism which acts to lift a lid onto the ramps, aswill be described later.

An overhead bar 251 extends across the width of the delivery bed 206 andis situated between the feed ports 209 and the ramps 248 and rollers250. The overhead bar 251 forms a wall of the feed ports 209. Theoverhead bar 251 is spaced above the delivery bed 206 at a height togive sufficient clearance for a well plate to pass underneath. On theoverhead bar 251 there are fastened a plurality of mounts 254, one aboveeach delivery lane 208. Protruding from each mount 254 is an overheadarm 252 which extends along the axial direction of the delivery lane208. Each overhead arm 252 is hingedly mounted in its mount 254 suchthat it is hinged about an axis parallel to the plane of the deliverybed 206 and perpendicular to the length of the delivery lanes 208. Eachoverhead arm 252 is spring-loaded within its mount 254 such that it isbiased to a position in which the free end of the arm is located at aheight substantially the same as the height of the ramps 248 at the endsof the arms 252. Under light pressure, however, each arm 252 is able tomove on its hinge such that its free end moves upwards.

FIG. 19 shows a perspective view of the underside of the well platestacker apparatus 200. The cassettes 216 may be seen protruding abovethe apparatus 200. Beneath each stacking port 212 is located a pneumaticpiston 256 which is movable in a vertical direction. Each piston 256 hasa connecting plate 258 attached to its upper end; the connecting plate258 connects the piston 256 to the four lifting members 214 of thatparticular stacking port 212. Operation of the pistons 256 thereforemoves the lifting members 214 up and down. The piston 256 and liftingmembers 214 comprise a lifting device or transfer mechanism.

Also shown in the Figure are the spring loaded arm mounts 264 of therollers 250.

Also shown is the sliding plate 260 of one of the delivery lanes 208(a).The sliding plate 260 is a flat elongate plate having tapered corners262 on its end facing towards the stop bar 245. The width of the slidingplate 260 at this end, between the tapered corners 262, is less than thespacing of the roller mounts 264 when in their biased position. The fullwidth of the plate behind these front corners, however, is wider thanthe spacing of the roller mounts 264, so that when the sliding platepasses between the roller mounts 264 the mounts 264 and hence therollers 250 mounted thereon are pushed apart so that the spacing betweenthem is increased. The length of the sliding plates 260 is such that theroller mounts 264 and rollers 250 are maintained in this pushed apartposition even when the sliding plate 260 has moved the pushing dog 242mounted thereon to its extreme position.

The well plate stacker apparatus 200 is configured to handle wellplates. These plates are containers for holding biological samples, andhave within them a quantity of small wells or depressions arranged in aregular matrix pattern. Well plates typically have the same dimensionsas the omni-trays discussed earlier, so have a footprint of 128 mm by 86mm.

FIG. 20 shows a cross-sectional view of a well plate 270. The well platecomprises a base 272 from which a side wall 274 extends upwards. Aflange 276 extends outwardly from the bottom of the side wall all theway around the well plate 270. The well plate 270 has a lid 278 whichhas the form of a flat surface with a side wall 280 extending downwardlyaround its edge. The lid 278 fits over the well plate 270 such that theside wall 280 of the lid 278 encompasses the side wall 274 of the wellplate 270, and extends downwardly to meet the flange 276. Therefore,there is no overhang to the lid of the well plate 270. The interior 281of the well plate 270 contains a quantity of wells as described above.The well plate has a rectangular footprint. Well plates are also knownin the art as micro-tite plates.

The well plate stacker apparatus 200 is controlled by a computercontroller (not shown), which operates the motors which drive thesliding plates 260. The apparatus 200 is provided with two microswitchesper delivery lane 208. One of the microswitches controls the escapementmechanism 210, and the other microswitch controls the piston 256. Themicroswitches are activated by movement of the pushing dogs 242 on theirsliding plates 260, as will be described in more detail later.

Operation of the well plate stacker apparatus 200 will now be described.

One, two or three cassettes 216 are filled with well plates. Eachcassette 216 holds up to fifty well plates, although cassettes holding alarger quantity of plates may be provided if desired. Each of the filledcassettes 216 is inserted into a feed port 209 of the apparatus 200. Aspreviously described, the legs 228 of the inserted cassette 216 protrudethrough the apertures 235 in the feed ports 209, so that the bottom-mostwell plate in the stack rests on the supporting flanges 234 of theescapement mechanism 210, rather than on the latches 230 of the cassette216.

An empty cassette 216 is inserted into each stacking port 212 which isbehind a feed port 209 having a filled cassette 216. The stacking ports212 do not have apertures 235 like those in the feed ports 209;therefore the cassettes 216 inserted into the stacking ports 212 sitwith the ends of their legs 228 on the flat bed 202 of the apparatus200.

The computer controller sends a command to initiate operation of theapparatus 200. One, two or all three of the delivery lanes 208 areselected for use as desired. For each selected lane, the commandactivates the motor controlling the sliding plate 260, so that thepushing dog 242 begin to move from its home position 213 behind theempty cassette 216 in the stacking port 212, towards the full cassette216 in the feed port 209. The pushing dog 242 then passes and activatesthe microswitch which controls the escapement mechanisms 210.

FIGS. 21( a), 21(b) and 21(c) are simplified cross-sectional diagramsillustrating the operation of the escapement mechanism of the feed port209. As shown in FIG. 21( a), a stack of (in this example) three wellplates 270 are supported on the supporting flange 234 of an escapementmechanism 210. The lowest well plate 270(a) rests directly on thesupporting flange 234. Activation of the escapement mechanism 210 causesthe hinged member 233 to pivot about its hinge such that the supportingflange 234 begins to move outwards away from the well plates 270, andthe gripping portion 236 begins to move inwards towards the well plates270. The relative sizes of the gripping portion 236 and the supportingflange 234 are such that the gripping portion 236 comes into contactwith the side of the second-from-bottom well plate 270(b) before thesupporting flange 234 has moved completely away from under thebottom-most well plate 270(a). Hence the second-to-bottom well plate270(b) is gripped between the gripping portions 236 of the escapementmechanisms 210 on each side of it. This situation is depicted in FIG.21( b). The hinged member 233 continues to pivot until the supportingflange 234 moves completely out from beneath the bottom-most well plate270(a), so that this well plate falls past the supporting flange and onto the flat bed 202 at the bottom of the feed port 209 (a firstposition). The gripping portion 236 continues to grip thesecond-from-bottom well plate 270(b), so that the stack of well platesabove this well plate is supported thereon.

While the well plate 270(a) is being released, the pushing dog 242continues to move along the delivery lane 208. At this time the pick-upcatch 244 is in its inoperable position and hence does not protrudeabove the delivery bed 206. The pushing dog 242 moves forward until itcontacts the rear wall of the well plate 270 in the feed port 209 andbegins to push the well plate 270 forward so that it passes underneaththe overhead bar 251.

The well plate 270 then enters the lid handling assembly 218. Theinclined rollers 250, on each side of the delivery lane 208, makecontact with the lid 278 of the well plate 270. As the rollers 250 arespaced by slightly less than the width of the well plate lid 278, theyare pushed outwards slightly by the pressure of the advancing well plate270 and its lid 278 as allowed for by their arm mounts 264. However, thespring-biasing of the rollers 250 maintains contact between the rollers250 and the well plate lid 278, and the rubber surface of the rollers250 provides for high friction contact.

FIGS. 22( a), 22(b), 22(c) and 22(d) show simplified cross-sectionaldiagrams of the removal of a well plate lid 278 by the inclined rollers250 and ramp 248. FIG. 22( a) shows the well plate 272 with its lid 278being pushed by the pushing dog 242 towards the rollers 250. FIG. 22( b)shows a point at which the rollers 250 have begun to lift the lid 278from the well plate 270. When the rollers 250 contact the lid 278, theybegin to rotate freely about their axles, allowing the lid 278, which isbeing pushed by the pushing dog 242, to pass between them, and at thesame time lifting the lid owing to the grip of the rollers 250 upon thelid, and the inclined axis of rotation of the rollers 250. The pushingdog 242 continues to push the lid 278 and well plate 270 forward throughthe rollers. The rollers continue to lift the lid and feed it out abovethe ramp 248.

The sliding plate 260, at this point, passes between the spring-loadedroller mounts 264 and pushes them apart. Hence the rollers 250 also moveapart and release their grip upon the lid 278. The lid 278 is thereforedropped onto the ramps 248. The pushing dog 242 continues to push thewell plate 270 and its lid 278 forwards, with the lid 278 proceeding upthe ramp 248. Eventually the lid 278 is lifted so far up the ramp 248that the bottom edge of its side wall is lifted above the height of thepushing dog 242, so that the pushing dog 242 ceases to push the lid 278any further forward and merely pushes the well plate 270 forward on itsown. The pushing dog 242 continues to push the well plate 270 throughthe lid handling assembly, so that the lid 278 remains behind sitting onthe ramps 248. FIG. 22( d) shows this.

As the lid 278 climbs the ramps it pushes the spring-loaded overhead arm252 upwards. However, the biasing of the overhead arm 252 keeps the freeend of the arm 252 pressing down upon the lid 278, so that when the lid278 is fully lifted onto the ramps 248 the downward pressure of theoverhead arm 252 maintains the lid 278 in its lifted position on theramps 248. Hence the overhead arm 252 acts as a retainer, to retain thelid 278 in position.

The pushing dog 242 continues to push the well plate 270 along to theend of the delivery lane 208, until the well plate 270 touches thestop-bar 245 (a second position). The spring-loaded nature of thepushing dog 242 means that the well plate 270 is maintained in tightcontact with the stop-bar 245 so that the well plate 270 is securelyheld in position. When the second position the well plate 270 is readyto receive samples. The samples are typically delivered by amicro-arraying process, in which a movable overhead array of pins orneedles pick up samples from colonies in other containers such asQ-trays, and deposit the samples in the wells of the well plate 270.This process is typically computer controlled.

Once samples have been deposited in the well plate 270, the well plate270 is ready to be delivered back to a cassette 216. Therefore thecomputer controller sends a command to the motor once again, and themotor direction is reversed so that the sliding plate moves in adirection towards the feed port 209 and the stacking port 212. Thereversal of the motor also activates the pick-up catch 244 so that itmoves into its picking up position, protruding above the surface of thedelivery bed 206. Conventional well plates have in their bottom surfacea recess, into which the pick-up catch enters. Hence the pick-up catch244 pulls the well plate 270 along the delivery lane 208. The pushingdog 242 passes under the lid 278 held on the ramps 248. However, theramps are arranged so that rear edge of the side wall of the lid 278 isheld at a height lower than the height of the side wall of the wellplate 270. Therefore, the rearwardly moving well plate 270 engages withthe rear wall of the lid 278 and begins to pull the lid down the ramp248. The rollers 250 are still held in their spaced apart position owingto the sliding plates 260 forcing the spring-loaded roller mounts 264apart, so that the well plate 270 is able to pull its lid 278 freelythrough the rollers 250 so that the lid 278 slides off the end of theramp 248 and drops back onto its well plates 272. Hence the lid 278 isreplaced correctly on the well plate 270.

The pick-up catch 244 continues to pull the well plate 270 so that itpasses right underneath the stack of well plates held in the cassette216 located in the feed port 209 (and hence passes through the firstposition). These well plates are still supported by the grippingportions 236 of the escapement mechanisms 210, so that there is amplespace for the well plate 270 to pass beneath. The pick-up catch 244continues to drag the well plate 270 until it is located underneath theempty cassette 216 positioned in the stacking port 212 (a thirdposition). At this point, the pushing dog 242 has returned to its homeposition 213. The pick-up catch then returns to its inoperable position,under the flat bed 202. As the pushing dog 242 returns to the homeposition 213 it activates the second microswitch, which operates thepiston 256. The piston 256 moves upwards so that the lifting members 214pass through the apertures 238 in the flat bed 202 and come into contactwith the lower surface of the well plate 270. The lifting members 214continue to move upwards carrying the well plate 270 with them. The wellplate lid 278 makes contact with the second surfaces 229 of the latches230 so that the protrusions 232 on the latches 230 are pushed inside thelegs 228 of the cassette 216. Hence the well plate 270 can pass beyondthe latches 230, the protrusions 232 of which spring back into theprotruding position once the well plate 270 has passed. The liftingmembers 214 are then lowered by reversal of the direction of movement ofthe piston 256, and the well plate 270 comes to rest on the protrusions232 of the latches 230.

The escapement mechanisms 210 in the feed port 209 now move so that thehinged member 233 rotates back to its original position. Hence thesupporting flanges 234 extend below the stack of well plates within thecassette 216 and the gripping portions 236 release the originalsecond-from-bottom well plate 270(b) so that it falls onto thesupporting flanges 234 and becomes the new bottom-most well plate in thestack. Hence the well plate stacker apparatus 200 is returned to itsoriginal configuration, with one well plate 270 per selected deliverylane 208 provided with samples and transferred to an empty cassette 216.

The computer controller is now able to send further commands to theapparatus 200 to repeat the process described above, in which the wellplates 270 now at the bottom of the stacks in the cassettes 216 in thefeed ports 209 are carried along the delivery lanes 208, supplied withsamples, and transferred to the cassettes 216 in the stacking ports 212.Hence in this way each of the well plates is sequentially removed fromits cassette 216 via the feed ports 209 supplied with samples, andtransferred to a cassette 216 in one of the stacking ports 212. At theend of the process, when all of the well plates 270 have beentransferred from one cassette 216 to the other, the well plates 270 arestacked in the stacking port cassette 216 in reverse order to that inwhich they were stacked within the feed port cassette 216. This isbecause each new well plate 270 is transferred to the stacking portcassette 216 by being pushed upwards by the lifting members 214 so thateach successive well plate 270 passes the latches 230 and becomes thebottom-most well plate in the stack contained within the stacking portcassette 216, supported on the protrusions 232. (In fact, this is aconvenient way to manually fill a storage cassette with blank wellplates, e.g. by lowering the cassette over a stack of well platesarranged on a bench.)

FIG. 23 shows a simplified cross-section of one of the ramps 248. Thesloping surface of the ramp 248 is divided into two portions, a lowerramp portion 282 and an upper ramp portion 284. The lower portion 282has a much shallower incline or gradient than the upper portion 284. Arubber strip 286 is provided on the surface of the lower portion 282, toprovide friction. As a lid 278 is removed, the rollers 250 and pushingdog 242 push the lid 278 up the ramps 248 until the front edge of thelid 278 is on the steeply inclined upper ramp portion 284. However, inorder for a well plate 270 to be able to pick up its lid 278 on thereturn travel, it is necessary for the rear edge of the lid 278 to belower than the height of the side wall of the well plate. To ensure thatthis happens, the upper portion 284 of the ramp 248 has a steep inclineand a low friction surface, so that the lid can slide down the ramp 248under gravity, until the front edge hits the rubber strip 286. Frictionprovided by the rubber strip 286 prevents the lid 278 from sliding rightoff the ramp 248, and retains the lid 278 in the correct position to bepicked up by the returning well plate 270.

Therefore, the well plate stacker apparatus is able to deliver andretrieve well plates for arraying, and remove and correctly replace thelids without having to bring the moving plates to a standstill. Thus alarge number of plates can be handled automatically and quickly. Theapparatus as described can be modified by the provision of more deliverylanes, so that more than three well plates can be delivered at one time.Also, the delivery lanes can be operated independently, to provideflexibility for the user.

Additionally, a lid handling assembly of the type described for use withwell plates, and featuring rollers to lift a non-overhanging lid, isalso suitable for use with containers having overhanging lids ifdesired. Clearly, however, the rollers increase the complexity of theassembly, so that the use of a ramps-only configuration is to bepreferred for handling overhanging lids.

Similarly, features of either the container feeder apparatus or the wellplate stacker apparatus may be combined as desired, because there arefeatures performing similar functions in each apparatus. For example,well plates may be loaded onto an elevator and conveyed using aconveying device with two clamping jaws as described for Q-trays, if thejaws are suitable sized. Alternatively, well plates are the same sizeand shape as omni trays, so that well plates could be held in omni trayholders and handled by the container feeder apparatus.

Third Embodiment

It is common in arraying techniques for colonies to be picked fromQ-trays, omni trays or petri dishes, and transferred to well plates.Therefore, the first and second embodiments may be combined in a singlearraying apparatus which is loaded with colony-containing containers andwith empty well plates, and which then removes the lids and delivers thecontainers as required to an arraying surface where a pin arraytransfers samples from the containers to the well plates, and retrievesthe containers after use, replacing the lids in the process.

FIG. 24 shows a simplified schematic block diagram of an embodiment ofsuch an arraying apparatus, viewed from above.

The arraying apparatus 300 has an arraying surface 302, around which arepositioned a container feeder apparatus 10 and a well plate stackerapparatus 200. The container feeder apparatus has a housing 12containing two elevator stacks 34, and a conveyor assembly 26 having twoconveyors 44 each provided with a lid handling assembly 63. The conveyorassembly 26 extends across the arraying surface 302 so that containersmay be delivered from the elevator stacks 34 to the arraying surface302. The well plate stacker apparatus 200 has a delivery bed 206 withthree delivery lanes 208 each having a lid handling assembly 218. Eachdelivery lane has a corresponding feed port 209 and a stacking port 212.The delivery bed 206 extends across the arraying surface 302 so thatwell plates may be delivered from cassettes in the feed ports 209 to thearraying surface 302.

The arraying apparatus 300 also has an arraying assembly 304, which hasa motorised drive system controlled by a computer, for operating anarraying arm 306 which extends above the arraying surface 302. The arm306 terminates in a pin head 308 which holds a plurality of pins 310arranged in a matrix, which can be dipped down into containers andplates on the arraying surface 302. The arraying arm 306 is moveableover the arraying surface 302 to an extent such that every pin 310 canreach every well in each of the three well plates delivered to thearraying surface 302 at any time, and every part of each of thecontainers delivered to the arraying surface 302 at any time. Hencesamples can be transferred from any of the containers to any of the wellplate wells. The pin head 308 also houses a camera (not shown) operableto photograph colonies in a container before arraying begins. Thecomputer processes the photograph to calculate spatial co-ordinates ofthe position of the colonies on the arraying surface 302; theseco-ordinates are then used to direct the arraying arm 306 so that thepins 310 accurately pick the colonies. The computer may also be used tocontrol the well plate stacker apparatus 200 and the container feederapparatus 10; alternatively, separate computers may be provided forthis.

A pin head can also be used for gridding. In addition, a liquid handlinghead having an array of pipette tips could also be used. Therefore, thearraying apparatus can be considered in more general terms as providinga work surface over which a head carrying pins or pipettes can be moved,to transfer biological material between different container types.

The well plate stacker apparatus 200 and the container feeder apparatus10 are operated in the manner described above. In other words, theconveyor assembly 26 of the container feeder apparatus 10 conveyscontainers from a first pick-up position within the housing 12 anddelivers them, via a first lid handling assembly 63 to a first sprayingposition on the arraying surface 302. The delivery lanes 208 of the wellplate stacker apparatus 200 convey well plates from a second pick-upposition, in the feed ports 209, via a second lid handling assembly 218,so a second arraying position on the arraying surface 302. Once colonypicking and arraying for these containers and well plates has beencompleted, the conveyor assembly 26 returns the containers to the firstpick-up position via the first lid handling apparatus 63, and thedelivery lanes 208 convey the well plates to a return position in thestacker ports 212, via the second lid handling assembly 218. This isrepeated as necessary until as many containers as desired have beenpresented for arraying.

Arraying assemblies operable in the above-described manner are known.However, by combining this type of assembly with a well plate stackerapparatus and a container feeder apparatus according to the presentinvention, the arraying process can be speeded up significantly,allowing larger volumes of samples to be processed in less time than ispossible with prior art configurations.

Further Embodiments

First Alternative Lid Handling Assembly

FIG. 25 shows a perspective view of an alternative embodiment of a lidhandling assembly 399. Like the lid handling assembly 218 of the secondembodiment, this lid handling assembly 399 uses rollers to assistlifting a container lid onto a pair of ramps.

The lid handling assembly 399 comprises a pair of elongate mountingblocks 400, arranged longitudinally one on either side of a deliverylane 208 such as those discussed previously. The sides of the mountingblocks 400 which face each other are each provided with an inclined ramp401. The ramps 401 slope upwards in the longitudinal direction of thedelivery lane 208, and protrude slightly into the delivery lane 208. Thelower end of each ramp 401 is located a small distance behind one end ofthe respective mounting blocks 400. The ramps 401 have a bottom edgewhich is spaced above the surface of the delivery lane 208 so as toleave a clearance gap 406.

Each mounting block 400 is further provided with a recess 402 at its endadjacent to the lower ramp end, and longitudinally spaced aparttherefrom. In each recess 402 there is mounted a roller 403, the rollers403 being each mounted on an axle 404 on which the rollers can freelyrotate. The axles 404 and rollers 403 are mounted such that the axis ofrotation of the rollers is inclined at a small angle to the vertical.For example, an angle in the range 1° to 10° or 1° to 5° could be used,such as 4°. Also, the rollers protrude slightly over the delivery lane.The axles 404 are fixed to the mounting blocks 400 so that the rollerscan rotate but cannot move laterally.

The lid handling assembly 399 works in a similar fashion to thatdescribed in relation to the second embodiment (see FIG. 22 andaccompanying text), in that the rollers 403 act to lift a lid off acontainer passing between them, and feed the lid onto the ramps 401 asthe container passes between the ramps 401. However, the constructionand operation of the lid handling assembly 399 are simplified by the useof rollers having fixed axles. The rollers 403 are positioned such thatthey protrude into the path of an oncoming container only far enough tocontact the lid of the container with sufficient friction to lift it.Because there is no biasing of the rollers 403 towards the lid (otherthan by the resilience of the rubberised roller faces), this contact isnot sufficient to grip the lid between the rollers 403, and the lid ismerely directed upwardly by the rollers 403. Hence there is norequirement for any kind of biasing release mechanism to separate therollers 403 so as to drop the lid onto the ramps 401. Similarly, on thereturn journey, the friction between the lid and the rollers is easilyovercome by the pulling or pushing force of the conveying device used toconvey the container along the delivery lane, so that the lid is pulledback onto the container.

The size of the clearance gap 406 can be altered so as to accommodatelarger or smaller containers and/or conveying devices. The ramps 401need to be an appropriate distance above the delivery lane 208 for thelifting provided by the rollers 403 to be sufficient to deliver the lidonto the ramps 401, otherwise the lid will merely collide with the endsof the ramps 401 and not be removed from its container. The clearancegap 406 can be altered, for example, by the use of one or more spacerplates (not shown) beneath the mounting blocks 400, or by providing anumber of alternative interchangeable mounting blocks 400 for differenttypes of well plates. Unfortunately, there is no standardization of theouter dimensions of well plates so different pairs of blocks need to beprovided for different proprietary well plate types. However, themounting block pairs are easily mounted and demounted to allowrelatively easy changeover between different well plate types.

Also shown in FIG. 25 is a lid detection system comprising anoptoelectronic transducer 408 mounted on one of the mounting blocks 400,and an optical source 410, such as an LED, mounted on the other mountingblock 400. Each of these components is mounted at a height less than thedepth of a lid above the respective ramp 401. The transducer 408 isarranged to detect light emitted by the optical source 410 and deliveran electronic signal in response. The electronic signal from thetransducer 408 can be fed to a computer or control circuit used tocontrol the apparatus of which the lid handling assembly 399 forms apart. The presence of a lid on the ramps 401 will interrupt the lightemitted by the optical source 410 and hence the transducer 408 will notdetect anything. This arrangement thus detects the presence or absenceof a lid on the ramps 401, and allows problems to be indicated. Forexample, the apparatus can be halted, or an alarm given, if a lid failsto be properly deployed onto the ramps 401 or returned to its container.

This optoelectronic system is an alternative to a microswitch-basedsystem.

This lid handling assembly 399 can be used with containers havingoverhanging or non-overhanging lids, including well plates, Q-trays,omni-trays and petri dishes.

Second Alternative Lid Handling Assembly

FIG. 26 shows a perspective view of a further alternative embodiment ofa lid handling assembly 420 which relies solely on rollers and has noramps. Mounted on each side of a delivery lane 208 of the type describedabove are roller assemblies 421. Each roller assembly 421 comprises apair of mounts 422 fastened adjacent to the delivery lane 208, with aroller arm axle 424 extending between the mounts 422 in a longitudinaldirection with respect to the delivery lane 208. The roller arm axle 424has mounted upon it a roller arm 426. The roller arm 426 issubstantially elongate in shape and has an inclined upper surface 427.The roller arm 426 is rotatable about the roller arm axle 424, but isprovided with a biasing mechanism (not shown), which biases the rollerarm 426 such that the upper surface 427 is rotated slightly towards thedelivery lane 208 and the opposite roller assembly 421. The biassingmechanism may comprise a suitable spring or springs, such as acompression spring acting between the arm 426 and the block 422.

The upper surface 427 of each roller arm 426 has a three roller axles430 extending substantially perpendicularly therefrom and disposed alongthe length of the roller arm 426. A freely-rotatable roller 428 ismounted on each roller axle 430. The incline of the upper surface 427means that the rollers 428 rotate about parallel axes which are inclinedat a few degrees to the vertical. The rollers 428 are arranged on eachroller arm 426 so that pairs of rollers are located on opposite sides ofthe delivery lane 208. As before, the rollers 428 may suitably eachcomprise a plurality of ball races stacked one upon the other, andsurrounded by a tubular sleeve of a rubber material having a highcoefficient of friction, such as santoprene. The biasing of the rollerarms 426 is arranged such that the spacing between each pair of rollers428 is slightly less than the width of a lid of a container to behandled by the lid handling assembly 420. Also, the lowest roller pairis arranged to be at substantially the same height above the delivery208 lane as a lid on a container being conveyed along the delivery lane208.

Operation of the lid handling assembly 420 is as follows. A containerhaving a lid, which may or may not be of the overhanging type, isconveyed along the delivery lane by any convenient method, such as theconveying devices already described, and approaches the lid handlingassembly 420 from the lower end of the roller arms 428. As the containerand lid reaches the lid handling assembly 420, the lid abuts the lowestpair of rollers. The pressure of the lid against the rollers 428 forcesthe roller arms 426 to rotate away from each other until the lid andcontainer can pass between the rollers 428, although the biasing of theroller arms 426 causes the rollers 428 to grip the lid. The rollers 428rotate against the moving lid, and the inclined axis of rotation of therollers 428 causes the rollers 428 to begin lifting the lid as thecontainer moves forwards.

Similar gripping and lifting of the lid then occurs at the second andthird pairs of rollers, until the lid has been completely removed fromthe container. The container is further conveyed along the deliverylane, and the lid remains gripped between the rollers because of thebiasing of the roller arms 426, and hence suspended above the deliverylane 208.

When the container returns in the opposite direction, it engages withthe rear wall of the suspended lid, and drags the lid down and out frombetween the rollers 428 until the lid falls onto the container. Theroller arms 426 are then free to rotate back to their biased positions,ready for the next container.

A larger or smaller number of rollers than the three pairs shown in FIG.26 may alternatively be provided, depending on the size of the rollersand of the lid to be handled. It is expected that most conveniently two,three, four or five roller pairs would be provided. However, a singleroller pair may be used for handling a relatively small lid, if thebiassing of the roller arms and the friction of the rollers provides anadequate grip on the lid.

A number of the subsidiary features of the various lid handlingassemblies described herein can be included as desired in otherembodiments. For example, the lid detection system shown in FIG. 25 canusefully be combined with any of the embodiments, as can appropriatelymodified versions of the spring loaded arms and guide arms shown in FIG.13. Also, any of the various ramp and/or roller arrangements can beprovided with a sufficient length to remove two or more lids at onetime, as illustrated in FIGS. 10 and 13.Alternative Well Plate Release Mechanism

FIGS. 27( a) to 27(f) show schematic diagrams of a release mechanismwhich provides an alternative embodiment to the escapement mechanismshown in FIG. 21, for releasing a well plate from a cassette placed in afeed port, and locating the well plate in the correct position for it tobe conveyed. In this embodiment, the escapement mechanism is replaced bya gripper mechanism and a piston mechanism which operate in conjunction.

FIG. 27( a) shows a plurality of well plates 270 which are stackeddirectly one upon the other. The well plates 270 are held within acassette of the type shown in FIG. 15 and the cassette itself is mountedin a feed port 209 of a well plate stacker apparatus such as thatdescribed in the second embodiment. The cassette and the feed port arenot shown for the sake of clarity. The lower three well plates 270 aregripped from two sides by a pair of grippers 430. The grippers 430support the stack of well plates retained within the cassette so thatthe well plate stack is suspended above a delivery bed 206 of the wellplate stacker apparatus. The delivery bed 206 has four holes 431 (onlytwo of which are shown in FIG. 27) passing through it, the through holesbeing arranged directly below the stack of well plates 270 so that eachhole aligns with a corner of the well plate above. Arranged below thedelivery beds 206 is a piston mechanism (not shown in these schematicFigures). The piston mechanism comprises a support device having fourvertical support rods 432 which pass through the four holes 431 in thedelivery bed 206. The lower ends of the support rods 432 are mounted ona horizontal rod support plate 434 below the delivery bed 206. Anabutment plate 436, the purpose of which will be explained in duecourse, is rotatably mounted on the underside of the rod support plate434. The support rods 432, the rod support plate 434 and the abutmentplate 436 are all mounted on a piston assembly, which is not shown. Thepurpose of the piston assembly is to raise and lower the support rods432, and the rod support plate 434.

In FIG. 27( a), the piston mechanism 433 is shown in a fully retracted,bottom position, in which the upper ends of the support rods 432 do notprotrude above the surface of the delivery bed 206. To deliver a wellplate from the cassette the piston mechanism 433 is operated such thatthe support rods 432 are pushed upwards through the delivery bed 206until they reach a support, top position in which they abut the lowestwell plate 270 a held by the grippers 430. This is shown in FIG. 27( b).Then, the grippers 430 are moved horizontally outwards so that theycease to grip the stack of well plates 270, which remain supported onthe support rods 432, as is shown in FIG. 27( c).

The support rods are then lowered to an intermediate position by adistance ‘d’ equivalent to the height of a single well plate, carryingthe stack with them, as shown in FIG. 27( d). The lowest well plate 270a in the well plate stack is thus now located just below the level ofthe grippers 430. FIG. 27( e) shows the next position in the releasesequence, in which the grippers are moved horizontally inwards so as togrip the well plate stack again. However, because the stack has alreadybeen lowered, the grippers 430 do not come into contact with the lowestwell plate 270 a. The piston mechanism 433 then lowers the support rods432 back down the retracted position. The lowest well plate 270 a islowered also and comes to rest on the delivery bed 206. The lowest wellplate 270 a is thus now located in the correct position for conveying,and can be moved along the delivery bed 206 in an horizontal directionby a suitable conveying device, such as a dog or a carriage. After thelowest well place 270 a has been moved, the gripper mechanism and pistonmechanism are back in their original positions as shown in FIG. 27( a),with the exception that a different well plate 270 b is now in thelowest position, arranged ready for subsequent release.

As is evident from FIG. 27, the piston mechanism may be deployed intoany one of three vertical positions. These are the retracted, bottomposition, in which the support rods are approximately at the level ofthe delivery bed 206, the support, top position in which the supportrods abut the lower surface of a stack of well plates, and also extendsubstantially to the height of the grippers 430, and the intermediateposition, in which the support rods 432 abut the stack of well plates,but support them at a height such that the lowest well plate is belowthe level of the grippers 430. Prior to loading a full cassette of wellplates into feed port, it is necessary to position the support rods 432into their support position. In this way, they will engage with andsupport the stack of well plates as the cassette is inserted. Thegrippers 430 can then move inwards to grip the stack of well plates, sothat the release, locating and conveying of the plates may begin. Amicroswitch or similar may be provided in the feed port so that thesupport rods 432 are automatically deployed into the support positionwhen a cassette is removed from the feed port, so that they are ready toreceive a further stack of well plates when the next cassette isinserted.

This embodiment means that the release mechanism can be readily adaptedto handle well plates or other containers of differing thicknesses. Wellplates conventionally come in two thicknesses, thin and thick. A thinwell plate has a thickness of approximately 20 cm and a thick well platehas a thickness of approximately 30 cm. All that is required is that theintermediate position of the support rods 432 be such that the distance‘d’ shown in FIG. 27( d) corresponds to the thickness of the lowest wellplate or other container 270 a.

The present embodiment is further advantageous in that the grippers 430are configured to grip the stack of well plates by coming into contactwith a plurality of well plates at the bottom of the stack, includingthe lowest well plate. This distributes the pressures exerted on thewell plate stack, and helps to prevent bowing of the well plates, whichcan occur if more localized gripping is used, in particular with thehinged arrangement of the second embodiment (see FIGS. 21( a) to 21(c)).

Gripper Mechanism

As is evident from FIG. 27, the grippers 430 take the form of a pair ofopposing plates with substantially parallel vertical surfaces. Thevertical surfaces may be provided with a high friction resilientcoating, such as rubber, to provide better grip on the well plates. Thegrippers operate by being moved towards and away from the well platestack in a horizontal direction. Therefore, they may be driven by anymechanism suitable to provide this motion. For example, pistons ormotor-driven worm drives may be employed. However, in many instances itis desirable to keep the size of the gripper mechanism to a minimum, sothat adjacent delivery lanes of a stacker apparatus may be more closelyspaced. One way of achieving this is to provide a gripper mechanismwhich utilizes levers to provide the horizontal motion.

FIG. 28 is a perspective view of a feed port 209 of a well plate stackerapparatus incorporating the gripper mechanism. Certain parts of theapparatus are not drawn in order to allow the important parts of thegripper mechanism to be seen. The substantially horizontal delivery bed206 may be seen. A well plate cassette 216 is arranged in the feed port209, no well plates are shown. A gripper 430 is shown, having asubstantially flat vertical face which faces towards the position wherea stack of well plates would be contained within the cassette insertedin the feed port 290. The opposite gripper 430 is obscured by itsmounting components. Each gripper 430 is attached by four screws 440 toa mounting plate 442. Each mounting plate 442 is disposed within anaperture 444 in a vertically mounted support plate 446. The mountingplate 442 is attached to the support plate 446 by upper and lowerpivoting arms 448, 450 which are arranged such that the gripper 430 onthe mounting plate 442 can be moved backwards and forwards in ahorizontal direction while the face of the gripper 430 is keptsubstantially vertical. Movement of the mounting plate 442 and gripper403 is provided by a system of levers 452. The lever system 452comprises an upper lever 452 a, which is pivotally connected at one endto the mounting plate 442, a lower lever 452 b which is arranged belowthe delivery bed 206 and connected at one end to a drive mechanism, andintermediate levers connecting the upper lever 452 a to the lower lever452 b and passing through a suitably sized opening 454 in the deliverybed 206. The drive mechanism (not shown), which is a single hydraulicpiston located symmetrically below the delivery bed 206, operates tomove both the lower levers 452 b upwards, and this motion is transferredvia the lever system 452 and the pivot arms 448, 450 to give horizontalmovement of the grippers 430 towards each other. The arrangementdepicted in FIG. 28 shows the two lower levers 452 b associated with thetwo grippers 430 connected to a single drive mechanism. The arrangementis simple and convenient, but alternatively separate drive mechanismsmay be used to drive the individual grippers. This may be suitable if itis desired to provide independent motion of the grippers. Any drivemechanism capable of providing appropriate motion between two positionsmay be used.

Also evident in FIG. 28 are support posts 451 which bolt the hydraulicpiston assembly 464 to the underside of the delivery bed 206.

FIG. 29 a is a perspective rear view of a single gripper mechanism,shown in a retracted position, in which the associated gripper ispositioned away from a well plate stack (as in FIG. 27( c), forexample). FIG. 29 b is a perspective view of the same gripper mechanism,but this time arranged such that the associated gripper 430 is in anadvanced position, so as to grip any well plate present in the feed port290 (as in FIG. 27( a), for example).

Other arrangements of lever and pivots may be used to provide thenecessary motion of the grippers.

Piston Mechanism

As mentioned previously, the support rods 432, the rod support plate 434and the abutment plate 436 of the piston mechanism are moved verticallyby a piston assembly.

FIG. 30 shows a series of schematic diagrams of the piston assembly 464.The piston assembly 464 comprises a horizontal piston support plate 460,which is bolted to the underside of the delivery bed 206 by the foursupport posts 451 that can be seen in FIG. 28 but which are not shown inFIGS. 30( a) to 30(c). The piston support plate 460 supports on itsunderside three pistons. A main piston 462 is located approximatelycentrally on the piston support plate, and is flanked by two subsidiarypistons 472 arranged one on each side of the main piston 462. Thesubsidiary pistons 472 have a shorter stroke than the main piston 462.The main piston 462 has a main piston rod 470 which is verticallymoveable through an aperture in the piston support plate 460. Similarly,the subsidiary pistons 472 each have a subsidiary piston rod 474 whichis also vertically moveable through an aperture in the piston supportplate 460. The pistons are each hydraulic two position pistons.

FIG. 30( a) shows the support rods 432 in their retracted position, inwhich they do not protrude much above the delivery bed 206. In thisposition, the abutment plate 436 rests on the piston support plate 460and three piston rods are fully retracted within their respectivepistons.

FIG. 30( b) shows the support rods 432 in the intermediate position.This is provided by extension of the subsidiary piston rods 474, whichabut the abutment plate 436, and hence support the support rods 432 inthe intermediate position. The length of the subsidiary piston rods 474is such that the support rods 432 protrude only partly through thedelivery bed 206. As illustrated in FIG. 30( b), in the intermediateposition, the main piston rod 470 is fully retracted within the mainpiston 462.

FIG. 30( c) shows the support rods 432 in the support position, in whichthey protrude by the maximum possible amount through the support bed206, so as to support a stack of well plates so that the lowest wellplate is between the grippers 430 of the release mechanism. The supportposition is achieved by moving the main piston rod 470 into its extendedposition, in which it abuts the abutment plate 436 and pushes the rodsupport plate 432 up against the underside of the delivery bed 206. Thearrangement in FIG. 30( c) shows the subsidiary piston rods 474 extendedfrom the subsidiary pistons 472. However, they may also be retractedwhen the support rods are in the support position, since they have noeffect in this position.

Thus, the support rods may be moved directly between the retractedposition (FIG. 30( a)) and the support position (FIG. 30( c)) byextension and retraction of the main piston rod 470. The subsidiarypistons 472 are used to provide the intermediate position. The operationof the support rods as described with reference to FIG. 27 requires thatthe intermediate position occur after the support position. To achievethis, the main piston rod 470 is extended to place the support rods 432in the support position, and then the subsidiary piston rods 474 arefully extended to the position shown in FIG. 30( c). Then, the mainpiston rod 470 is retracted to lower the support rods 432. During thelowering, the abutment plate 436 comes into contact with the extendedsubsidiary piston rods 474 so that the lowering of the support rods 432is stopped, and the support rods 432 are held in the intermediateposition. The main piston rod 472 continues retracting until thesituation illustrated in FIG. 30( b) is reached. If it is desired toposition the support rods in the intermediate position from theretracted position, it is merely necessary extend the main piston rods474 which will push the support rods 432 upwards.

Pneumatic or hydraulic pistons may be used for the subsidiary pistons472 and the main piston 462, as preferred. The pistons may be controlledby a computer or other control device, which may also be used to operateother parts of the well plate stacker apparatus.

The purpose of the abutment plate 436 is to provide height adjustment ofthe intermediate position, so that the piston mechanism and grippermechanism can accommodate well plates and containers of varyingthickness. Referring to FIG. 27( d), it can be seen that the distance‘d’ by which the well plate stack is lowered to release the bottom wellplate is determined by the well plate thickness. To provide thecapability of handling both thick and thin well plates, the apparatusmust allow for lowering by d_(thick) and d_(thin) as desired, whered_(thin)<d_(thick).

FIG. 31( a) shows a schematic side view of the piston mechanism in adirection perpendicular to the views shown in FIG. 30. Consequently,only one subsidiary piston 474 is visible (the main piston 462 is notshown for the sake of clarity). As before, the delivery bed 206 can beseen, with the support rods 432 extending through it, mounted on the rodsupport plate 434. The abutment plate 436 is shown on the underside ofthe rod support plate 434 with the subsidiary piston 470 and itsassociated subsidiary piston rod 474 positioned below by the pistonsupport rods 476 which extend vertically through the abutment plate 436and the rod support plate 434.

The abutment plate is rotatable about a substantially central verticalaxis. The lower side of the abutment plate 436 is provided with a pairof holes 478 arranged on opposite sides of its width and also a pair ofprotrusions 480 similarly arranged on opposite sides of the width.Conveniently, a hole 478 and a protrusion 480 are positioned angularlyadjacent to one another with their centers equidistant from the rotationaxis of the rotatable abutment plate 436. The pair of holes andsimilarly the pair of protrusions are each located such that when theabutment plate is suitably positioned, one or other pair coincides withthe subsidiary piston rods 474 when these are in their extendedposition. Rotation of the abutment plate is conveniently performed by asuitably-located movable needle which abuts the abutment plate and whoseposition is controllable by a pneumatic feed line. However, othermovement methods may be alternatively used. Actuation of the needle 482is controlled by the apparatus control system to allow switching betweendifferent well plate thicknesses.

In the arrangement depicted in FIG. 31( a), the abutment plate isrotated so that the subsidiary piston rods 474 coincide with the holes478 in the abutment plate 436. Therefore, when the support rods arelowered into their intermediate position, the subsidiary piston rods 474enter the holes 478 in the abutment plate 436 so that the support rodsare lowered more than they would be in the absence of the holes. This isused to release a “thick” well plate from the stack.

To accommodate a “thin” well plate, the abutment plate is rotated untilthe protrusions 480 align with the subsidiary piston rods 474. In thiscase, when the support rods are lowered, the protrusions align with andabut the subsidiary piston rods 474 and the downward motion of thesupport rods 432 is arrested at a higher level than when the depression478 are aligned with the subsidiary piston rods 474. This is depicted inFIG. 31( b).

If desired, a number of holes and protrusions of varying sizes may beprovided on the abutment plate, to give more than two distances ‘d’shown in FIG. 27( d). However, in practice, well plates typically areavailable in only two thickness, so that the abutment plate shown inFIG. 31 a is sufficient. It will also be understood that the samefunctionality can be provided with two differing protrusions, two holesof different depths, or by any other variable height abutment mechanism.One alternative that has been built and tested uses a rotatable cam toprovide different height abutments.

FIG. 32( a) is a perspective view of part of the abutment plate 436 inthe position shown in FIG. 30( c) and with the abutment plate 436rotated in the position shown in FIG. 31( a) for thick well plates. Theabutment plate 436 may be suitably made from metal or a plasticsmaterial. A hole 478 and its adjacent protrusion 480 are visible, withthe hole 478 aligned with the subsidiary piston rod 474, to providehandling of thick well plates. Note, however, that the subsidiary pistonrod 474 is not fully extended to enter the depression 478, as would bethe case if the support rods 432 were in the intermediate position. Theneedle 482 and pneumatic feed line 484 are also shown. The needle is inan extended position, to push the abutment plate 436 around.

FIG. 32( b) is a similar perspective view of the abutment plate to thatshown in FIG. 32( a). However, in this case the abutment plate 436 hasbeen rotated, by retraction of the needle 482, so that the protrusion480 is aligned with the subsidiary piston rod 474, to accommodate thinwell plates. A piston support rod 476 may also be seen in FIGS. 32( a)and 32(b).

FIG. 33 is a view from below showing the underside of part of a wellplate stacker apparatus incorporating the piston mechanism. Theapparatus has a delivery bed 206 configured to provide a single wellplate delivery lane. A feed port 209 is provided, together with astacking port 212 which returns well plates after conveying samples to acassette by means of a single vertically movable piston 256, asdescribed with reference to FIG. 19. Beneath the feed port 209 arelocated the main piston 462 and the two subsidiary pistons 472, arrangedone of each side of the main piston 462. Between the pistons and thedelivery bed 206 is the rotatable adjustment plates 436. The needle 482and its pneumatic feed line 484 may also be seen; the needle is in theextended position shown in FIG. 32( a).

FIG. 34 is a perspective view of the apparatus shown in FIG. 33, whichalso illustrates the gripper mechanism, and the lid handling apparatusfeaturing ramps with fixed rollers.

The apparatus has a delivery bed 206 having a single delivery lane 208,with a corresponding single feed port 209 and a single stacking port212. Each of the ports is shown with a cassette 216 inserted therein,although neither cassette contains any well plates.

The lid handling assembly 399 includes the pair of ramps 401 and rollers403 mounted on a pair of mounting blocks 400 positioned one on each sideof the delivery lane 208.

One side of the gripper mechanism can be seen, comprising the supportplate 446, the mounting plate 442, the upper and lower pivot arms 448,450, and the upper lever 452. One of the subsidiary pistons 472 and themain piston 462 are visible mounted below the delivery bed 206, as ispart of the abutment plate 436.

The apparatus further comprises a carriage 486 operable to convey a wellplate along the delivery lane 208. The carriage may be driven by anysuitable mechanism, such as a belt drive, or a worm drive, the formerbeing preferred since it can slip when the carriage is arrested. When awell plate is released from the cassette 216, the carriage 486 issituated below the cassette 216, in the feed port 209, so that the wellplate is lowered onto the carriage 486 by the support rods. This is thereason why the support rods protrude slightly above the delivery bed inthe retracted position; it is only necessary to lower them enough forthe well plate to come to rest on the carriage. The carriage provides analternative to the pushing dog and pick-up catch of the secondembodiment.

A particular advantage of the well-plate cassette described herein,together with the delivery system in the form of either the escapementmechanism or the gripper/piston mechanism is that the plates can bestacked in the cassettes directly one upon the other for handling. Notonly does this reduce space and hence allow more compact apparatus to beprovided, but it also makes the loading and unloading of cassettesbefore and after handling rapid and simple. It is much quicker for anoperator to load or unload a stack of plates into or out of a cassettethan it is to arrange individual plates on separate shelves of anelevator device or similar and remove them afterwards, i.e. the stacksystem described herein is much easier to load and unload than theconventional “hotel” systems. Hence, these aspects of the presentinvention permit arraying to be performed more quickly than is possiblewith prior art devices.

1. Apparatus for handling biological sample containers each having alid, the apparatus comprising: (a) a conveyor assembly operable toconvey containers between a first position and a second position; and(b) a lid handling assembly operable to remove lids from containersbeing conveyed through the lid handling assembly from the first positionto the second position, and to replace the lids onto containers beingconveyed through the lid handling assembly from the second position tothe first position, wherein: (i) lid removal and replacement beingeffected by mechanical interaction between the lids and the lid handlingassembly as the containers are conveyed through the lid handlingassembly, and (ii) the lid handling assembly comprises a pair ofrotatable rollers arranged such that the conveyor assembly conveys acontainer between the pair of rollers from the first position to thesecond position and from the second position to the first position, eachroller having an axis of rotation inclined with respect to aperpendicular to a plane in which the containers are conveyed, therollers operable to grip the lid of a container being conveyed betweenthe rollers from the first position to the second position and feed thelid in a forwardly and upwardly direction.
 2. Apparatus according toclaim 1, in which the lid handling assembly further comprises a pair oframps arranged such that the conveyor assembly conveys a containerbetween the pair of ramps from the first position to the second positionand from the second position to the first position, the ramps slopingupward from lower ramp ends facing towards the first position andarranged such that they pass under side walls of the lid of a containerbeing conveyed between the pair of ramps from the first position to thesecond position, wherein the rotatable rollers are located in front ofeach lower ramp end, the rollers being operable to direct the lid overthe lower ramp ends.
 3. Apparatus according to claim 2, in which therollers are biased towards one another to provide enhanced engagement ofthe rollers with the lid.
 4. Apparatus according to claim 2, in whichthe pair of ramps is arranged such that a lid removed from its containersits on the ramps at a height at which a lowest part of the lid engageswith a container being conveyed between the ramps from the secondposition to the first position so that the container pulls the lid downthe ramp until the lid falls onto the container.
 5. Apparatus accordingto claim 2, in which the ramps have a length sufficient to accommodatethe lids of at least two containers and the conveying apparatus isoperable to convey at least two containers from the first position tothe second position between the pair of ramps before conveying eithercontainer from the second position to the first position.
 6. Apparatusaccording to claim 2, in which the lid handling assembly furthercomprises one or more retainers operable to retain a lid or lids on thepair of ramps until the lid or lids is replaced on a container. 7.Apparatus according to claim 6, in which the one or more retainerscomprises a movable abutment on at least one of the ramps of the pair oframps which inhibits a lid or lids on the pair of ramps from slidingdown the ramps.
 8. Apparatus according to claim 6, in which the one ormore retainers comprise a spring-loaded hinged arm arranged above thepair of ramps and biased to push downwardly on a lid held on the ramps.9. Apparatus according to claim 2, in which each ramp has a portionhaving a steeper gradient than a subsequent portion, to provide rapidinitial lifting of a lid.
 10. Apparatus according to claim 2, in whicheach ramp has a portion having a shallower gradient than a subsequentportion, to encourage a lid to slide down the ramps under gravity. 11.Apparatus according to claim 1, in which each roller is pivotablymounted and biased towards the opposite roller, to enhance the grip ofthe pair of rollers upon the lid.
 12. Apparatus according to claim 1,and further comprising one or more additional pairs of rollers arrangedparallel to and rearwardly and upwardly from the first-mentioned pair ofrollers such that a gripped lid can be fed from roller pair to rollerpair as the container is conveyed between the rollers.
 13. Apparatusaccording to claim 1, in which the lid-handling assembly is removablymounted on the conveyor assembly.
 14. Apparatus according to claim 1, inwhich the lid handling assembly is configured to handle biologicalsample containers having the form of Q-trays.
 15. Apparatus according toclaim 1, in which the lid handling assembly is configured to handlebiological sample containers having the form of omni-trays. 16.Apparatus according to claim 1, in which the lid handling assembly isconfigured to handle biological sample containers having the form ofpetri dishes.
 17. Apparatus according to claim 1, in which the lidhandling assembly is configured to handle biological sample containershaving the form of well plates.
 18. Apparatus according to claim 1, andfurther comprising one or more additional conveyor assemblies and lidhandling assemblies, and operable to convey, remove lids from, andreplace lids onto, a plurality of containers simultaneously. 19.Apparatus according to claim 1, and further comprising a storageassembly operable to store a plurality of containers, to supply any ofthe stored containers to the first position for the container to beconveyed to the second position, and to remove the container from thefirst position after it has been conveyed from the second position tothe first position.
 20. Apparatus according to claim 1, in which theconveyor is further operable to convey containers from the firstposition to a third position after the containers have been conveyedfrom the second position to the first position.
 21. Apparatus accordingto claim 20, and further comprising a release mechanism operable torelease a single container from a stack of containers stored in a firststorage cassette removably mounted on the apparatus and to locate thesingle container at the first position.
 22. Apparatus according to claim21, in which the release mechanism comprises an escapement mechanismcomprising a pair of escapement members arranged one on each side of thefirst position and pivotable movable about horizontal axes between oneposition in which the escapement members supports the stack ofcontainers from beneath, a further position in which the escapementmembers grip the penultimate container in the stack and supports thelowest container in the stack from beneath, and a yet further positionin which the escapement members grip the penultimate container whileletting the lowest container fall into the first position.
 23. Apparatusaccording to claim 21, in which the release mechanism comprises: (a) apair of grippers operable to support the stack of containers by grippingat least the lowest container in the stack from two opposite sides; and(b) a vertically movable support device arranged below the stack ofcontainers and which is movable between a retracted position locatedsubstantially at the same height as the first position, (c) a supportposition in which the support device support the stack from below bycontacting the lowest container supported by the pair of grippers, and(d) an intermediate position separated from the support position by adistance corresponding to the thickness of a single container. 24.Apparatus according to claim 23, in which the intermediate position canbe adjusted so that the release mechanism can release and locatecontainers of different thicknesses.
 25. Apparatus according to claim23, and further comprising a piston assembly operable to move thesupport device between the retracted position, the intermediate positionand the support position, the piston assembly comprising a main pistonoperable to move the support device between the retracted position andthe support position, and at least one subsidiary piston operable tolocate the support device in the intermediate position.
 26. Apparatusaccording to claim 25, and further comprising an adjustable abutmenthaving portions of different thickness and operable to determine themovement of the subsidiary piston so as to alter the intermediateposition in which the subsidiary piston locates the support device. 27.Apparatus according to claim 23, in which the grippers comprise a pairof opposed vertical plates operable to move towards and away from eachother in a horizontal direction.
 28. Apparatus according to claim 20,and further comprising a lifting device operable to transfer a containerfrom the third position into a second storage cassette removably mountedon the apparatus.
 29. Apparatus according to claim 20, in which the lidhandling assembly is configured to handle for biological samplecontainers having the form of well plates.
 30. Apparatus according toclaim 20, and further comprising one or more additional conveyorassemblies and lid handling assemblies, and operable to convey, removelids from, and replace lids onto a plurality of containerssimultaneously.
 31. An apparatus for working with biological material,comprising: (a) a work surface; (b) a first container handlingapparatus, for handling biological sample containers containingbiological material, comprising: (i) a storage assembly operable tostore containers, deliver containers to a first pick-up position, andremove containers from the first pick-up position; (ii) a first conveyorassembly operable to convey containers between the first pick-upposition and a first working position on the work surface; and (iii) afirst lid-handling assembly operable to remove lids from containers asthey are conveyed through the first lid handling assembly from the firstpick-up position to a first arraying position and to replace the lidsonto the containers as they are conveyed through the first lid handlingassembly from the first arraying position to the first pick-up position,wherein lid removal and replacement is effected by mechanicalinteraction between the lids and the first lid handling assembly as thecontainers are conveyed through the first lid handling assembly; (c) asecond container handling apparatus, for handling well plates,comprising: (i) a well plate release mechanism operable to release wellplates from a first storage cassette containing a stack of well platesand to deliver them to a second pick-up position; (ii) a second conveyorassembly operable to convey well plates from the second pick-up positionto a second working position on the work surface and from the secondworking position to a return position; (iii) a second lid-handlingassembly operable to remove lids from well-plates as they are conveyedthrough the second lid handling assembly from the second pick-upposition to the second working position and to replace the lids onto thewell-plates as they are conveyed through the second lid handlingassembly from the second working position to the return position,wherein lid removal and replacement are effected by mechanicalinteraction between the lids and the second lid handling assembly as thecontainers are conveyed through the second lid handling assembly; and(iv) a well plate loading mechanism operable to transfer well platesfrom the return position into a second storage cassette; and (v) a headcarrying a plurality of pins or pipettes operable to move over the worksurface, pick up material from containers in the first working positionand deposit the material in well plates in the second working position.32. A method of handling biological sample containers each having a lid,the method comprising: (a) conveying a container with a lid from a firstposition through a lid handling assembly; (b) arranging a firstmechanical interaction between the lid and the lid handling assembly asthe container is conveyed through the lid handling assembly whichremoves the lid from the container; (c) conveying the container withoutits lid to a second position; (d) conveying the container without itslid from the second position through the lid handling assembly; (e)arranging a second mechanical interaction between the lid and the lidhandling assembly as the container is conveyed through the lid handlingassembly which replaces the lid onto the container; and (f) conveyingthe container with its lid back to the first position, wherein the firstmechanical interaction is effected by conveying the container between atleast one pair of rotatable rollers having parallel axes of rotationinclined with respect to a plane in which the containers are conveyed,each roller being biased towards the opposite roller, and arranged togrip the lid as the container is conveyed through the lid handlingassembly and feed the lid in a forwardly and upwardly direction.
 33. Amethod according to claim 32, in which the first mechanical interactionfurther is effected by conveying the container between a pair of rampshaving lower ramp ends which face towards the first position and arearranged to pass under side walls of the lid of the container as thecontainer is conveyed through the lid handling assembly, wherein atleast one pair of rotatable rollers is located in front of lower ends ofthe pair of ramps, and arranged to engage the lid as the container isconveyed through the lid handling assembly and to direct the lid ontothe ramps.